Adding flags when building bench with CMake (#9)

Since the gnu extensions where removed, executables in bench directory cannon be built correctly.
The fix is adding "-D_POSIX_C_SOURCE=200112L" on those targets. When -std=gnu99 was used,
bench worked without this flag, but that was not the case since we switched to -std=c99.

bench/CMakeLists.txt

@@ -152,6 +152,7 @@ function(benchexe extn)
                                 PRIVATE
                                 # load-var-for,COPTFLAGS
                                 ${COPTFLAGS}
+                                ${CPPROCFLAGS}
                             )
         if(WIN32 AND BUILD_SHARED_LIBS)
             target_compile_definitions(${exec_name}.x

bench/bench_aocl_gemm/CMakeLists.txt

@@ -55,6 +55,7 @@ function(lpgemmbenchexe extn)
                                 PRIVATE
                                 # load-var-for,COPTFLAGS
                                 ${COPTFLAGS}
+                                ${CPPROCFLAGS}
                             )
         if(WIN32 AND BUILD_SHARED_LIBS)
             target_compile_definitions(${exec_name}.x