ENH: two macros to check whether the C/CXX compiler supports a given flag:

CHECK_CXX_COMPILER_FLAG("-Wall" COMPILER_SUPPORTS_WALL)

Alex

Modules/CheckCCompilerFlag.cmake

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+# - Check whether the C compiler supports a given flag.
+# CHECK_C_COMPILER_FLAG(FLAG VARIABLE)
+#
+#  FLAG - the compiler flag
+#  VARIABLE - variable to store the result
+
+# Copyright (c) 2006, Alexander Neundorf, <[email protected]>
+#
+# Redistribution and use is allowed according to the terms of the BSD license.
+# For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+
+
+INCLUDE(CheckCSourceCompiles)
+
+MACRO (CHECK_C_COMPILER_FLAG _FLAG _RESULT)
+   SET(SAFE_CMAKE_REQUIRED_DEFINITIONS "${CMAKE_REQUIRED_DEFINITIONS}")
+   SET(CMAKE_REQUIRED_DEFINITIONS "${_FLAG}")
+   CHECK_C_SOURCE_COMPILES("int main() { return 0;}" ${_RESULT})
+   SET (CMAKE_REQUIRED_DEFINITIONS "${SAFE_CMAKE_REQUIRED_DEFINITIONS}")
+ENDMACRO (CHECK_C_COMPILER_FLAG)
+

Modules/CheckCXXCompilerFlag.cmake

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+# - Check whether the CXX compiler supports a given flag.
+# CHECK_CXX_COMPILER_FLAG(FLAG VARIABLE)
+#
+#  FLAG - the compiler flag
+#  VARIABLE - variable to store the result
+
+# Copyright (c) 2006, Alexander Neundorf, <[email protected]>
+#
+# Redistribution and use is allowed according to the terms of the BSD license.
+# For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+
+
+INCLUDE(CheckCXXSourceCompiles)
+
+MACRO (CHECK_CXX_COMPILER_FLAG _FLAG _RESULT)
+   SET(SAFE_CMAKE_REQUIRED_DEFINITIONS "${CMAKE_REQUIRED_DEFINITIONS}")
+   SET(CMAKE_REQUIRED_DEFINITIONS "${_FLAG}")
+   CHECK_CXX_SOURCE_COMPILES("int main() { return 0;}" ${_RESULT})
+   SET (CMAKE_REQUIRED_DEFINITIONS "${SAFE_CMAKE_REQUIRED_DEFINITIONS}")
+ENDMACRO (CHECK_CXX_COMPILER_FLAG)
+