diff --git a/build/exe.mk b/build/exe.mk
index 2d16cb66..7f3bf4dd 100644
--- a/build/exe.mk
+++ b/build/exe.mk
@@ -47,12 +47,10 @@ PROGRAM         = $(BINPATH)/$(PROGRAM_NAME)
 DEBUG_PROGRAM   = $(DEBUG_BINPATH)/$(PROGRAM_NAME)
 RELEASE_PROGRAM = $(RELEASE_BINPATH)/$(PROGRAM_NAME)
 
-debug   : CFLAGS = -g -O0 -DDEBUG $(CONFIG_CFLAGS) $(DEBUG_CFLAGS) -W -Wall -DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
-valgrind: CFLAGS = -g -O0 -DDEBUG $(CONFIG_CFLAGS) $(DEBUG_CFLAGS) -DFLAC__VALGRIND_TESTING -W -Wall -DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
-release : CFLAGS = -O3 -fomit-frame-pointer -funroll-loops -finline-functions -DNDEBUG $(CONFIG_CFLAGS) $(RELEASE_CFLAGS) -W -Wall -Winline -DFLaC__INLINE=__inline__ -DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
+debug   : CFLAGS := -g -O0 -DDEBUG $(CONFIG_CFLAGS) $(DEBUG_CFLAGS) -Wall -Wextra $(CFLAGS) -DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
+valgrind: CFLAGS := -g -O0 -DDEBUG $(CONFIG_CFLAGS) $(DEBUG_CFLAGS) -DFLAC__VALGRIND_TESTING -Wall -Wextra $(CFLAGS)-DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
+release : CFLAGS := -O3 -fomit-frame-pointer -funroll-loops -finline-functions -DNDEBUG $(CONFIG_CFLAGS) $(RELEASE_CFLAGS) -Wall -Wextra $(CFLAGS) -DFLaC__INLINE=__inline__ -DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
 
-CFLAGS   = $(CFLAGS) -Wmissing-prototypes -Wstrict-prototypes
-CXXFLAGS = $(CFLAGS)
 
 LFLAGS   = -L$(LIBPATH)
 
diff --git a/build/lib.mk b/build/lib.mk
index 09191089..d46db1b9 100644
--- a/build/lib.mk
+++ b/build/lib.mk
@@ -66,12 +66,9 @@ else
     LINKD       = $(CC) -shared
 endif
 
-debug   : CFLAGS = -g -O0 -DDEBUG $(CONFIG_CFLAGS) $(DEBUG_CFLAGS) -W -Wall -DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
-valgrind: CFLAGS = -g -O0 -DDEBUG $(CONFIG_CFLAGS) $(DEBUG_CFLAGS) -DFLAC__VALGRIND_TESTING -W -Wall -DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
-release : CFLAGS = -O3 -fomit-frame-pointer -funroll-loops -finline-functions -DNDEBUG $(CONFIG_CFLAGS) $(RELEASE_CFLAGS) -W -Wall -Winline -DFLaC__INLINE=__inline__ -DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
-
-CFLAGS   = $(CFLAGS) -Wmissing-prototypes -Wstrict-prototypes
-CXXFLAGS = $(CFLAGS)
+debug   : CFLAGS := -g -O0 -DDEBUG $(CONFIG_CFLAGS) $(DEBUG_CFLAGS) -Wall -Wextra $(CFLAGS) -DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
+valgrind: CFLAGS := -g -O0 -DDEBUG $(CONFIG_CFLAGS) $(DEBUG_CFLAGS) -DFLAC__VALGRIND_TESTING -Wall -Wextra $(CFLAGS) -DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
+release : CFLAGS := -O3 -fomit-frame-pointer -funroll-loops -finline-functions -DNDEBUG $(CONFIG_CFLAGS) $(RELEASE_CFLAGS) -Wall -Wextra $(CFLAGS) -DFLaC__INLINE=__inline__ -DVERSION=$(VERSION) $(DEFINES) $(INCLUDES)
 
 LFLAGS   = -L$(LIBPATH)