I'm working on an open source project for the iPhone, and have converted the project to use ARC and the Apple LLVM 3.0 compiler. However, the project relies on an external library built using a makefile as it is written in C. Currently, it uses GCC to compile, and during the make it references the ARC-ified Objective-C code which causes errors as some symbols (such as #autorelease) don't exist on pre-LLVM compilers.
But enough about that. My question is how can I convert this snippet of code:
VERSION=4.3
COPT = -F/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS${VERSION}.sdk/System/Library/Frameworks -F/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS${VERSION}.sdk/System/Library/PrivateFrameworks -I../../ -I../../Classes/ -I/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.0.sdk/usr/lib/gcc/arm-apple-darwin9/4.2.1/include -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS${VERSION}.sdk -L/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS${VERSION}.sdk/usr/lib -I/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS${VERSION}.sdk/usr/include/
COPT += -march=armv7-a -miphoneos-version-min=${VERSION} -I. -O3 -D__IPHONE__ -D_SNESPPC -DASM_SPC700 -DZLIB -DUNZIP_SUPPORT -DOLD_COLOUR_BLENDING -DUSE_SA1 -DSUPER_FX -DLSB_FIRST -DCPU_SHUTDOWN -DVAR_CYCLES
COPT += -fnested-functions -funsigned-char -ffast-math -fexpensive-optimizations -ftemplate-depth-36 -mstructure-size-boundary=32 -falign-functions=32 -falign-loops -falign-labels -falign-jumps -finline -finline-functions -fno-builtin -fno-common -fomit-frame-pointer -fpeel-loops -fstrength-reduce -funroll-loops -fstrict-aliasing
GCC = /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-gcc-4.2.1
GXX = /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-g++-4.2.1
STRIP = /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/strip
to use the LLVM compiler? I've tried modifying it to this:
VERSION=5.0
COPT = -F/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS${VERSION}.sdk/System/Library/Frameworks -F/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS${VERSION}.sdk/System/Library/PrivateFrameworks -I../../ -I../../Classes/ -I/Developer/Platforms/iPhoneOS.platform/Developer/usr/lib/clang/3.0/include -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS${VERSION}.sdk -L/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS${VERSION}.sdk/usr/lib -I/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS${VERSION}.sdk/usr/include/
COPT += -march=armv7-a -miphoneos-version-min=${VERSION} -I. -O3 -D__IPHONE__ -D_SNESPPC -DASM_SPC700 -DZLIB -DUNZIP_SUPPORT -DOLD_COLOUR_BLENDING -DUSE_SA1 -DSUPER_FX -DLSB_FIRST -DCPU_SHUTDOWN -DVAR_CYCLES
COPT += -fnested-functions -funsigned-char -ffast-math -fexpensive-optimizations -ftemplate-depth-36 -mstructure-size-boundary=32 -falign-functions=32 -falign-loops -falign-labels -falign-jumps -finline -finline-functions -fno-builtin -fno-common -fomit-frame-pointer -fpeel-loops -fstrength-reduce -funroll-loops -fstrict-aliasing
GCC = /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/clang
GXX = /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/clang++
STRIP = /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/strip
But this targets the i386 architecture, instead of the ARM architecture for iOS, so I get errors such as:
"i386/types.h" not found
Is there a special version of clang for ARM? Or am I completely missing something?
Try -arch armv7; you need to explicitly specify the target to build for ARM with clang.
Related
Description
I'm trying build iphonesimulator-only targeted library witn architecture arm64, but linking step failed with error:
${LDCMD:-/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang} -O3 -fvisibility=hidden -miphoneos-version-min=9.0 -fembed-bitcode -fPIC -arch arm64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator14.5.sdk -L. -Wl,-search_paths_first \
-o apps/openssl apps/asn1pars.o apps/ca.o apps/ciphers.o apps/cms.o apps/crl.o apps/crl2p7.o apps/dgst.o apps/dhparam.o apps/dsa.o apps/dsaparam.o apps/ec.o apps/ecparam.o apps/enc.o apps/errstr.o apps/gendsa.o apps/genpkey.o apps/genrsa.o apps/nseq.o apps/ocsp.o apps/openssl.o apps/passwd.o apps/pkcs12.o apps/pkcs7.o apps/pkcs8.o apps/pkey.o apps/pkeyparam.o apps/pkeyutl.o apps/prime.o apps/rand.o apps/rehash.o apps/req.o apps/rsa.o apps/rsautl.o apps/s_client.o apps/s_server.o apps/s_time.o apps/sess_id.o apps/smime.o apps/speed.o apps/spkac.o apps/srp.o apps/storeutl.o apps/ts.o apps/verify.o apps/version.o apps/x509.o \
apps/libapps.a -lssl -lcrypto
ld: building for iOS, but linking in .tbd file (/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator14.5.sdk/usr/lib/libSystem.tbd) built for iOS Simulator, file '/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator14.5.sdk/usr/lib/libSystem.tbd' for architecture arm64
Configuraton command:
./Configure iossimulator-xcrun threads no-shared "-fvisibility=hidden -miphoneos-version-min=9.0 -fembed-bitcode -fPIC" no-asm no-hw no-async --prefix=/Users/macosuser/Build/OpenSSL/Install "-arch arm64" "-isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator14.5.sdk"
Configuring OpenSSL version 1.1.1j (0x101010afL) for iossimulator-xcrun
Using os-specific seed configuration
Creating configdata.pm
Creating Makefile
Build commands look like this:
...
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -I. -Iinclude -Iapps -O3 -fvisibility=hidden -miphoneos-version-min=9.0 -fembed-bitcode -fPIC -arch arm64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator14.5.sdk -D_REENTRANT -DNDEBUG -MMD -MF apps/x509.d.tmp -MT apps/x509.o -c -o apps/x509.o apps/x509.c
...
Question
I can't figure out why for other architectures (i386, x86_64) the build happens without problems.
Perhaps I am missing some nuance, but I cannot understand which one.
Why do I need this - an application using this library must run on a simulator in a macbook with an M1 processor.
Environment specifications
MacOS 11.4
XCode v12.5
OpenSSL v1.1.1j
Compiler - AppleClang 12.0.5.12050022
Because i'm not an iOS developer, i didn't immediately understand the specifics of building libraries through make for this platform.
The problem was this:
-miphoneos-version-min specifies the deployment target for iOS, but since i am building library for the iOS simulator, me need to use -mios-simulator-version-min.
As a result, the configuration command should look like this:
./Configure iossimulator-xcrun threads no-shared "-fvisibility=hidden -mios-simulator-version-min=9.0 -fembed-bitcode -fPIC" no-asm no-hw no-async --prefix=/Users/macosuser/Build/OpenSSL/Install "-arch arm64" "-isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator14.5.sdk"
If anyone can explain why the -miphoneos-version-min flag works as expected for i386 and x86_64 architectures, i would be grateful.
I'm trying to build a static cryptopp library for ios. I'm basing my steps from these sites:
http://cryptopp.com/wiki/IOS_(Command_Line)#Xcode_Project
https://github.com/noloader/cryptopp-5.6.2-ios
https://www.cryptopp.com/
1.) I downloaded the latest cryptopp version 5.6.3
2.) I downloaded noloader's cryptopp-5.6.2-ios becasue it has updated:
setenv-ios.sh - i had to edit this to search for sdk 9.2
GNUmakefile
config.h
build-for-ios.sh
3.) I copied the four files to my cryptopp 5.6.3 directory and replaced GNUmakefile and config.h
4.) I checked out IOS_Command_Line instruction to invoke setenv-ios.sh first.
5.) Then, as noloader said, run build-for-ios.sh.
However, i'm getting this error:
Has anyone successfully built the library using the latest ios SDK and cryptopp version? If so, can you please point me to the right direction. Thanks.
The documentation was not correct under IOS (Command Line) | Build the Library. After setting the environment with setenv-ios.sh, you should use GNUmakefile-cross:
$ make -f GNUmakefile-cross static dynamic cryptest.exe
clang++ -DNDEBUG -g2 -Os -fPIC -pipe -Wall -Wno-delete-non-virtual-dtor -arch armv7 -isysroot
/Applications/Xcode-5_1.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.1.sdk
-stdlib=libc++ -c cryptlib.cpp
clang++ -DNDEBUG -g2 -Os -fPIC -pipe -Wall -Wno-delete-non-virtual-dtor -arch armv7 -isysroot
/Applications/Xcode-5_1.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.1.sdk
-stdlib=libc++ -c cpu.cpp
clang++ -DNDEBUG -g2 -Os -fPIC -pipe -Wall -Wno-delete-non-virtual-dtor -arch armv7 -isysroot
/Applications/Xcode-5_1.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.1.sdk
-stdlib=libc++ -c 3way.cpp
...
I thought we updated the iOS procedures when we updated the Android procedures. I'm not sure what went wrong the documentation updates.
We checked in the scripts for setenv-ios.sh, setenv-android.sh and setenv-embedded.sh in March 2016. GNUmakefile-cross was already in the library. Also see Commit a78b9dfa0840f92f, Added iOS environment and test script and Commit 22d6374ce7151ad0, Added Android and embedded environment and test script.
All you should need to do now is the following:
git clone https://github.com/weidai11/cryptopp.git
cd cryptopp
. ./setenv-ios.sh
make -f GNUmakefile-cross static dynamic cryptest.exe
...
The new/updated files will be available in the ZIP at the next Crypto++ release, which will be either 5.6.4 or 5.7.0.
It is possible to get gcc configure options with gcc -v (an example is here). Is there a similar way to retrieve the compilation options of clang?
My real task is the following one: I have an environment with a compiler (clang) which I want to improve. Now I have some patch for clang that I applied and I want to rebuild the patched sources, but I also want to be sure that nothing changes from the vanilla build apart from my patch; in particular, that all the build flags I use are the same.
No, probably not. But it's possible to get the CXXFLAGS/LDFLAGS clang was compiled with via llvm-config.
$ llvm-config --cxxflags
-I/opt/compiler/llvm-trunk/include -march=native -fPIC -fvisibility-inlines-hidden -Wall -W -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wcovered-switch-default -Wnon-virtual-dtor -std=c++11 -ffunction-sections -fdata-sections -O3 -DNDEBUG -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS
$ llvm-config --ldflags
-L/opt/compiler/llvm-trunk/lib
$ llvm-config --system-libs
-lrt -ldl -lcurses -latomic -lpthread -lz -lm
If you are on a Linux distribution, then simply check the PKGBUILD (or similar) to find the exact flags.
Here is part of my compilation result:
===============================================================================
You are ready to build VLC and its contribs
make: '.gas' is up to date.
[info] Building contrib for iOS in '/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/contrib/iPhoneOS-arm64'
[info] LD FLAGS SELECTED = '-L/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk/usr/lib -arch arm64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk -miphoneos-version-min=5.1'
/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc
error: invalid deployment target '5.1.0' for architecture 'arm64' (requires
'7.0.0' or later)
1 error generated.
make: Nothing to be done for `fetch'.
error: invalid deployment target '5.1.0' for architecture 'arm64' (requires
'7.0.0' or later)
1 error generated.
sed -i.orig s/-ansi// freetype/builds/unix/configure
cd freetype && GNUMAKE=make CC="xcrun clang" CXX="xcrun clang++" LD="xcrun ld" AR="xcrun ar" CCAS="gas-preprocessor.pl xcrun clang -c" RANLIB="xcrun ranlib" STRIP="xcrun strip" PATH="/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/contrib/arm-apple-darwin11-arm64/bin:/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/extras/tools/build/bin:/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/extras/tools/build/bin:/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/contrib/arm-apple-darwin11/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin" CPPFLAGS="-isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk -arch arm64 -miphoneos-version-min=5.1 -O3 -g -arch arm64 -miphoneos-version-min=5.1 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk -arch arm64 -miphoneos-version-min=5.1 -O3 -g -I/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/contrib/arm-apple-darwin11-arm64/include" CFLAGS="-isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk -arch arm64 -miphoneos-version-min=5.1 -O3 -g -arch arm64 -miphoneos-version-min=5.1 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk -arch arm64 -miphoneos-version-min=5.1 -O3 -g -I/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/contrib/arm-apple-darwin11-arm64/include -g" CXXFLAGS="-isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk -arch arm64 -miphoneos-version-min=5.1 -O3 -g -arch arm64 -miphoneos-version-min=5.1 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk -arch arm64 -miphoneos-version-min=5.1 -O3 -g -arch arm64 -miphoneos-version-min=5.1 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk -arch arm64 -miphoneos-version-min=5.1 -O3 -g -I/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/contrib/arm-apple-darwin11-arm64/include -g -I/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/contrib/arm-apple-darwin11-arm64/include -g" LDFLAGS="-L/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk/usr/lib -arch arm64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk -miphoneos-version-min=5.1 -arch arm64 -miphoneos-version-min=5.1 -L/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk/usr/lib -arch arm64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk -miphoneos-version-min=5.1 -L/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/contrib/arm-apple-darwin11-arm64/lib" ./configure --without-png --prefix="/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/contrib/arm-apple-darwin11-arm64" --build="arm-apple-darwin11" --host="x86_64-apple-darwin11" --target="x86_64-apple-darwin11" --program-prefix="" --enable-static --disable-shared --disable-dependency-tracking --with-pic
FreeType build system -- automatic system detection
The following settings are used:
platform unix
compiler xcrun clang
configuration directory ./builds/unix
configuration rules ./builds/unix/unix.mk
If this does not correspond to your system or settings please remove the file
`config.mk' from this directory then read the INSTALL file for help.
Otherwise, simply type `make' again to build the library,
or `make refdoc' to build the API reference (the latter needs python).
cd builds/unix; /bin/sh ./configure '--without-png' '--prefix=/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/contrib/arm-apple-darwin11-arm64' '--build=arm-apple-darwin11' '--host=x86_64-apple-darwin11' '--target=x86_64-apple-darwin11' '--program-prefix=' '--enable-static' '--disable-shared' '--disable-dependency-tracking' '--with-pic'
configure: WARNING: unrecognized options: --disable-dependency-tracking
checking build system type... arm-apple-darwin11
checking host system type... x86_64-apple-darwin11
checking for x86_64-apple-darwin11-gcc... xcrun clang
checking whether the C compiler works... no
configure: error: in `/Users/nikhil.t/VLCKit/MobileVLCKit/ImportedSources/vlc/contrib/iPhoneOS-arm64/freetype/builds/unix':
configure: error: C compiler cannot create executables
See `config.log' for more details
make[1]: *** [setup] Error 77
make: *** [.freetype2] Error 2
===================================================================
I am using guideline provided by VLC
I tried to change the xcrun path in build.sh (ImportedSources/vlc/extras/package/ios/build.sh) but it resets to original once I build the script.
Is there another way I could change this, so that c compiler works for me?
I am stuck on this for the last 9 days, please provide some guidance.
Thanks,
Albin.K.J
The first error is:
error: invalid deployment target '5.1.0' for architecture 'arm64' (requires
'7.0.0' or later)
... so I would suggest trying what it suggests: bumping the deployment target up from 5.1.0 to 7.0.0, or remove arm64 support.
May be wrong compiler path.
Check the CC points to the correct path also it is as expected in the script file.
I also have the same issue, setting CC correctly did the trick for me.
The required compilers are missing from your system. You need both a C++ compiler and a C compiler.
You can install the compilers (GCC and G++) using apt-get install gcc g++.
I'd like to change from using GCC version 4.2 to LLVM version 2.0 in XCode4.
When I change the compiler flag to to LLVM I get an error: invalid value '' in '-std='. Was having it in the *_prefix.pch file, but after turning off the GCC_Precompile_prefix_header the error moved to a new point in my code.
The initial value use seems to refer to an empty string.
What's going on here.
The full error message is below.
Many thanks
CompileC /Users/cram/Library/Developer/Xcode/DerivedData/MightyMemory-cceuiavwfpmibiczfvlodqgugfnb/Build/Intermediates/MightyMemory.build/Debug-iphonesimulator/MightyMemory.build/Objects-normal/i386/GameViewController.o Classes/GameViewController.m normal i386 objective-c com.apple.compilers.llvm.clang.1_0.compiler
cd /Users/cram/Projects/MightyMemory
setenv LANG en_US.US-ASCII
setenv PATH "/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/opt/local/bin:/usr/local/git/bin"
/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/clang -x objective-c -arch i386 -fmessage-length=0 -fdiagnostics-print-source-range-info -fdiagnostics-show-category=id -fdiagnostics-parseable-fixits -std= -Wno-trigraphs -fpascal-strings -O0 -Wreturn-type -Wparentheses -Wswitch -Wno-unused-parameter -Wunused-variable -Wunused-value -isysroot /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator4.3.sdk -fexceptions -fasm-blocks -mmacosx-version-min=10.6 -gdwarf-2 -fvisibility=hidden -fobjc-abi-version=2 -fobjc-legacy-dispatch -D__IPHONE_OS_VERSION_MIN_REQUIRED=40000 -iquote /Users/cram/Library/Developer/Xcode/DerivedData/MightyMemory-cceuiavwfpmibiczfvlodqgugfnb/Build/Intermediates/MightyMemory.build/Debug-iphonesimulator/MightyMemory.build/MightyMemory-generated-files.hmap -I/Users/cram/Library/Developer/Xcode/DerivedData/MightyMemory-cceuiavwfpmibiczfvlodqgugfnb/Build/Intermediates/MightyMemory.build/Debug-iphonesimulator/MightyMemory.build/MightyMemory-own-target-headers.hmap -I/Users/cram/Library/Developer/Xcode/DerivedData/MightyMemory-cceuiavwfpmibiczfvlodqgugfnb/Build/Intermediates/MightyMemory.build/Debug-iphonesimulator/MightyMemory.build/MightyMemory-all-target-headers.hmap -iquote /Users/cram/Library/Developer/Xcode/DerivedData/MightyMemory-cceuiavwfpmibiczfvlodqgugfnb/Build/Intermediates/MightyMemory.build/Debug-iphonesimulator/MightyMemory.build/MightyMemory-project-headers.hmap -I/Users/cram/Library/Developer/Xcode/DerivedData/MightyMemory-cceuiavwfpmibiczfvlodqgugfnb/Build/Products/Debug-iphonesimulator/include -I/Users/cram/Library/Developer/Xcode/DerivedData/MightyMemory-cceuiavwfpmibiczfvlodqgugfnb/Build/Intermediates/MightyMemory.build/Debug-iphonesimulator/MightyMemory.build/DerivedSources/i386 -I/Users/cram/Library/Developer/Xcode/DerivedData/MightyMemory-cceuiavwfpmibiczfvlodqgugfnb/Build/Intermediates/MightyMemory.build/Debug-iphonesimulator/MightyMemory.build/DerivedSources -F/Users/cram/Library/Developer/Xcode/DerivedData/MightyMemory-cceuiavwfpmibiczfvlodqgugfnb/Build/Products/Debug-iphonesimulator -include /Users/cram/Projects/MightyMemory/MaxMemory_Prefix.pch -c /Users/cram/Projects/MightyMemory/Classes/GameViewController.m -o /Users/cram/Library/Developer/Xcode/DerivedData/MightyMemory-cceuiavwfpmibiczfvlodqgugfnb/Build/Intermediates/MightyMemory.build/Debug-iphonesimulator/MightyMemory.build/Objects-normal/i386/GameViewController.o
error: invalid value '' in '-std='
I solved the problem. For the next person to run up against this: It turns out that the options that were passed to the compiler were incorrect; not that I changed them from what they were when using gcc. The error was that the GCC_C_LANGUAGE_STANDARD was not set, i.e. the argument that XCode4 put is was '' (a blank string). I set it to compiler default and all was good.