Clang 3.4 uses C99 by default, and Clang 3.6 uses C11 by default:
http://thread.gmane.org/gmane.comp.compilers.clang.devel/39379
GNU 4.9 uses C90 by default, and GNU 5.0 uses C11 by default:
https://gcc.gnu.org/gcc-5/changes.html
Test that the default compiler settings result in the expected dialect
macros being defined for both C and CXX. Remove the unused main.c
file from the CompileFeatures unit test.
Add properties and variables corresponding to CXX equivalents.
Add features for c_function_prototypes (C90), c_restrict (C99),
c_variadic_macros (C99) and c_static_assert (C11). This feature
set can be extended later.
Add a <PREFIX>_RESTRICT symbol define to WriteCompilerDetectionHeader
to conditionally represent the c_restrict feature.
This moves GNU compiler flags into new-style modules
Compiler/GNU-<lang>.cmake
Platform/<os>-GNU-<lang>.cmake
We use language-independent helper modules
Compiler/GNU.cmake
Platform/<os>-GNU.cmake
to define macros consolidating the information.
This teaches CMake to detect implicit link information for C, C++, and
Fortran compilers. We detect the implicit linker search directories and
implicit linker options for UNIX-like environments using verbose output
from compiler front-ends. We store results in new variables called
CMAKE_<LANG>_IMPLICIT_LINK_LIBRARIES
CMAKE_<LANG>_IMPLICIT_LINK_DIRECTORIES
The implicit libraries can contain linker flags as well as library
names.
Stephen Kelly
Brad King