cmake: check platform early

ConfigureChecks.cmake

@@ -1,24 +1,35 @@
 include(CheckCSourceCompiles)
-include(TestBigEndian)
 include(CheckIncludeFile)
 include(CheckSymbolExists)
 include(CheckStructHasMember)
 
-check_include_file(cpuid.h HAVE_CPUID_H)
+set(CMAKE_REQUIRED_INCLUDES ${CMAKE_CURRENT_SOURCE_DIR})
 
-if (HAVE_CPUID_H)
-    check_symbol_exists(__get_cpuid "cpuid.h" HAVE___GET_CPUID)
+check_c_source_compiles(
+  "#include <stdio.h>
+int main() {
+  #include \"src/is_supported_platform.h\"
+}"
+  IS_SUPPORTED_PLATFORM)
+if(NOT IS_SUPPORTED_PLATFORM)
+  message(FATAL_ERROR "The target platform is not supported!")
 endif()
 
-check_include_file(execinfo.h HAVE_EXECINFO_H)
+set(CMAKE_REQUIRED_INCLUDES)
 
-if (OpenMP_FOUND)
+check_include_file(cpuid.h HAVE_CPUID_H)
+if(HAVE_CPUID_H)
+  check_symbol_exists(__get_cpuid "cpuid.h" HAVE___GET_CPUID)
+endif()
+
+check_include_file(execinfo.h HAVE_EXECINFO_H)
 
-set(CMAKE_REQUIRED_FLAGS ${OpenMP_C_FLAGS})
-set(CMAKE_REQUIRED_LIBRARIES ${OpenMP_C_LIBRARIES})
-set(CMAKE_REQUIRED_INCLUDES ${OpenMP_C_INCLUDE_DIRS})
-check_c_source_compiles("
-#include <omp.h>
+if(OpenMP_FOUND)
+  set(CMAKE_REQUIRED_FLAGS ${OpenMP_C_FLAGS})
+  set(CMAKE_REQUIRED_LIBRARIES ${OpenMP_C_LIBRARIES})
+  set(CMAKE_REQUIRED_INCLUDES ${OpenMP_C_INCLUDE_DIRS})
+  check_c_source_compiles(
+    "#include <omp.h>
 
 static void sink(const int x, int a[])
 {
@@ -36,11 +47,12 @@ int main(void)
     sink(x, a);
 
     return 0;
-}" HAVE_OMP_FIRSTPRIVATE_WITH_CONST)
+}"
+    HAVE_OMP_FIRSTPRIVATE_WITH_CONST)
 
-set(CMAKE_REQUIRED_FLAGS)
-set(CMAKE_REQUIRED_LIBRARIES)
-set(CMAKE_REQUIRED_INCLUDES)
+  set(CMAKE_REQUIRED_FLAGS)
+  set(CMAKE_REQUIRED_LIBRARIES)
+  set(CMAKE_REQUIRED_INCLUDES)
 endif()
 
 #
@@ -49,40 +61,14 @@ endif()
 set(CMAKE_REQUIRED_FLAGS ${THREADS_PREFER_PTHREAD_FLAG})
 set(CMAKE_REQUIRED_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
 
-check_struct_has_member("struct __pthread_rwlock_arch_t"
-                        "__readers"
-                        "pthread.h"
-                        HAVE_THREAD_RWLOCK_ARCH_T_READERS
-                        LANGUAGE C)
+check_struct_has_member(
+  "struct __pthread_rwlock_arch_t" "__readers" "pthread.h"
+  HAVE_THREAD_RWLOCK_ARCH_T_READERS LANGUAGE C)
 
-check_struct_has_member("struct __pthread_rwlock_arch_t"
-                        "__nr_readers"
-                        "pthread.h"
-                        HAVE_THREAD_RWLOCK_ARCH_T_NR_READERS
-                        LANGUAGE C)
+check_struct_has_member(
+  "struct __pthread_rwlock_arch_t" "__nr_readers" "pthread.h"
+  HAVE_THREAD_RWLOCK_ARCH_T_NR_READERS LANGUAGE C)
 
 unset(CMAKE_REQUIRED_FLAGS)
 unset(CMAKE_REQUIRED_LIBRARIES)
-
-set(CMAKE_REQUIRED_INCLUDES ${CMAKE_CURRENT_SOURCE_DIR})
-
-check_c_source_compiles("#include <stdio.h>
-int main() {
-  #include \"src/is_supported_platform.h\"
-}" IS_SUPPORTED_PLATFORM)
-if (IS_SUPPORTED_PLATFORM)
-    message(STATUS "Is the target platform supported: ${IS_SUPPORTED_PLATFORM}")
-else()
-    message(FATAL_ERROR "The target platform is not supported!")
-endif()
-
-set(CMAKE_REQUIRED_INCLUDES)
-
-test_big_endian(BIGENDIAN)
-if(${BIGENDIAN})
-    # we do not really want those.
-    # besides, no one probably tried darktable on such systems
-    message(FATAL_ERROR "Found big endian system. Bad.")
-else()
-    message(STATUS "Found little endian system. Good.")
-endif(${BIGENDIAN})
+unset(CMAKE_REQUIRED_INCLUDES)