# determine the target arch # really only interested in the preprocessor here CHECK_C_SOURCE_COMPILES("#if !(defined(__x86_64__) || defined(_M_X64))\n#error not 64bit\n#endif\nint main(void) { return 0; }" ARCH_64_BIT) CHECK_C_SOURCE_COMPILES("#if !(defined(__i386__) || defined(_M_IX86))\n#error not 64bit\n#endif\nint main(void) { return 0; }" ARCH_32_BIT) set(ARCH_X86_64 ${ARCH_64_BIT}) set(ARCH_IA32 ${ARCH_32_BIT})