build: compiler warnings handling refactored for clang

cmake/warnings.cmake

@@ -53,7 +53,7 @@ macro(_set_flags)
         /permissive- # standards conformance mode for MSVC compiler.
     )
 
-    set(CLANG_WARNINGS
+    set(GCC_COMMON_WARNINGS
         -Wall
         -Wextra # reasonable and standard
         -Wpedantic # warn if non-standard C++ is used
@@ -67,17 +67,17 @@ macro(_set_flags)
         -Wconversion # warn on type conversions that may lose data
         -Wsign-conversion # warn on sign conversions
         -Wnull-dereference # warn if a null dereference is detected
-            -Wdouble-promotion # warn if float is implicit promoted to double
         -Wformat=2 # warn on security issues around functions that format output (ie printf)
     )
 
+    set(CLANG_WARNINGS
+        ${GCC_COMMON_WARNINGS}
+        -Wno-missing-braces
+    )
+
     set(GCC_WARNINGS
-            ${CLANG_WARNINGS}
-            -Wno-float-conversion
-            -Wno-shorten-64-to-32
-            -Wno-implicit-float-conversion
-            -Wno-implicit-int-float-conversion
-            -Wno-implicit-int-conversion
+        ${GCC_COMMON_WARNINGS}
+        -Wdouble-promotion # warn if float is implicit promoted to double
         -Wmisleading-indentation # warn if indentation implies blocks where blocks do not exist
         -Wduplicated-cond # warn if if / else chain has duplicated conditions
         -Wduplicated-branches # warn if if / else branches have duplicated code