Use separate makefile var for CFLAGS (#226)

CFLAGS now get initialized with the provided value for WASM_CFLAGS, or
its default.

This seems to be the intended use case of having `WASM_CFLAGS ?=` at the
top of the Makefile. Otherwise, if WASM_CFLAGS is set on the command
line, it overrides all CFLAGS and for example `--sysroot` is not added,
rendering the build invalid unless it is supplied on the make command
line.

diff --git a/Makefile b/Makefile
index 899469512cfd5f38214fc472cda71111b372ee11..c7ef1697fc51f4e878bef171f686626febdc6c70 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -184,21 +184,21 @@ LIBC_TOP_HALF_ALL_SOURCES = \
     $(shell find $(LIBC_TOP_HALF_SOURCES) -name \*.c)
 
 # Set the target.
-WASM_CFLAGS += --target=$(TARGET_TRIPLE)
+CFLAGS = $(WASM_CFLAGS) --target=$(TARGET_TRIPLE)
 # WebAssembly floating-point match doesn't trap.
 # TODO: Add -fno-signaling-nans when the compiler supports it.
-WASM_CFLAGS += -fno-trapping-math
+CFLAGS += -fno-trapping-math
 
 # Configure support for threads.
 ifeq ($(THREAD_MODEL), single)
-WASM_CFLAGS += -mthread-model single
+CFLAGS += -mthread-model single
 endif
 ifeq ($(THREAD_MODEL), posix)
-WASM_CFLAGS += -mthread-model posix -pthread
+CFLAGS += -mthread-model posix -pthread
 endif
 
 # Set the sysroot.
-WASM_CFLAGS += --sysroot="$(SYSROOT)"
+CFLAGS += --sysroot="$(SYSROOT)"
 
 # These variables describe the locations of various files and directories in
 # the build tree.
@@ -335,40 +335,40 @@ $(SYSROOT_LIB)/libwasi-emulated-signal.a: $(LIBWASI_EMULATED_SIGNAL_OBJS) $(LIBW
        # silently dropping the tail.
        $(WASM_AR) crs $@ $(wordlist 800, 100000, $^)
 
-$(MUSL_PRINTSCAN_OBJS): WASM_CFLAGS += \
+$(MUSL_PRINTSCAN_OBJS): CFLAGS += \
            -D__wasilibc_printscan_no_long_double \
            -D__wasilibc_printscan_full_support_option="\"add -lc-printscan-long-double to the link command\""
 
-$(MUSL_PRINTSCAN_NO_FLOATING_POINT_OBJS): WASM_CFLAGS += \
+$(MUSL_PRINTSCAN_NO_FLOATING_POINT_OBJS): CFLAGS += \
            -D__wasilibc_printscan_no_floating_point \
            -D__wasilibc_printscan_floating_point_support_option="\"remove -lc-printscan-no-floating-point from the link command\""
 
-$(LIBWASI_EMULATED_SIGNAL_MUSL_OBJS): WASM_CFLAGS += \
+$(LIBWASI_EMULATED_SIGNAL_MUSL_OBJS): CFLAGS += \
            -D_WASI_EMULATED_SIGNAL
 
 $(OBJDIR)/%.long-double.o: $(CURDIR)/%.c include_dirs
        @mkdir -p "$(@D)"
-       "$(WASM_CC)" $(WASM_CFLAGS) -MD -MP -o $@ -c $<
+       "$(WASM_CC)" $(CFLAGS) -MD -MP -o $@ -c $<
 
 $(OBJDIR)/%.no-floating-point.o: $(CURDIR)/%.c include_dirs
        @mkdir -p "$(@D)"
-       "$(WASM_CC)" $(WASM_CFLAGS) -MD -MP -o $@ -c $<
+       "$(WASM_CC)" $(CFLAGS) -MD -MP -o $@ -c $<
 
 $(OBJDIR)/%.o: $(CURDIR)/%.c include_dirs
        @mkdir -p "$(@D)"
-       "$(WASM_CC)" $(WASM_CFLAGS) -MD -MP -o $@ -c $<
+       "$(WASM_CC)" $(CFLAGS) -MD -MP -o $@ -c $<
 
 -include $(shell find $(OBJDIR) -name \*.d)
 
-$(DLMALLOC_OBJS): WASM_CFLAGS += \
+$(DLMALLOC_OBJS): CFLAGS += \
     -I$(DLMALLOC_INC)
 
-startup_files $(LIBC_BOTTOM_HALF_ALL_OBJS): WASM_CFLAGS += \
+startup_files $(LIBC_BOTTOM_HALF_ALL_OBJS): CFLAGS += \
     -I$(LIBC_BOTTOM_HALF_HEADERS_PRIVATE) \
     -I$(LIBC_BOTTOM_HALF_CLOUDLIBC_SRC_INC) \
     -I$(LIBC_BOTTOM_HALF_CLOUDLIBC_SRC)
 
-$(LIBC_TOP_HALF_ALL_OBJS) $(MUSL_PRINTSCAN_LONG_DOUBLE_OBJS) $(MUSL_PRINTSCAN_NO_FLOATING_POINT_OBJS) $(LIBWASI_EMULATED_SIGNAL_MUSL_OBJS): WASM_CFLAGS += \
+$(LIBC_TOP_HALF_ALL_OBJS) $(MUSL_PRINTSCAN_LONG_DOUBLE_OBJS) $(MUSL_PRINTSCAN_NO_FLOATING_POINT_OBJS) $(LIBWASI_EMULATED_SIGNAL_MUSL_OBJS): CFLAGS += \
     -I$(LIBC_TOP_HALF_MUSL_SRC_DIR)/include \
     -I$(LIBC_TOP_HALF_MUSL_SRC_DIR)/internal \
     -I$(LIBC_TOP_HALF_MUSL_DIR)/arch/wasm32 \
@@ -413,7 +413,7 @@ startup_files: include_dirs
        #
        @mkdir -p "$(OBJDIR)"
        cd "$(OBJDIR)" && \
-       "$(WASM_CC)" $(WASM_CFLAGS) -c $(LIBC_BOTTOM_HALF_CRT_SOURCES) -MD -MP && \
+       "$(WASM_CC)" $(CFLAGS) -c $(LIBC_BOTTOM_HALF_CRT_SOURCES) -MD -MP && \
        mkdir -p "$(SYSROOT_LIB)" && \
        mv *.o "$(SYSROOT_LIB)"
 
@@ -465,7 +465,7 @@ finish: startup_files libc
        #
        # Test that it compiles.
        #
-       "$(WASM_CC)" $(WASM_CFLAGS) -fsyntax-only "$(SYSROOT_SHARE)/include-all.c" -Wno-\#warnings
+       "$(WASM_CC)" $(CFLAGS) -fsyntax-only "$(SYSROOT_SHARE)/include-all.c" -Wno-\#warnings
 
        #
        # Collect all the predefined macros, except for compiler version macros
@@ -481,7 +481,7 @@ finish: startup_files libc
        @#
        @# TODO: Undefine __FLOAT128__ for now since it's not in clang 8.0.
        @# TODO: Filter out __FLT16_* for now, as not all versions of clang have these.
-       "$(WASM_CC)" $(WASM_CFLAGS) "$(SYSROOT_SHARE)/include-all.c" \
+       "$(WASM_CC)" $(CFLAGS) "$(SYSROOT_SHARE)/include-all.c" \
            -isystem $(SYSROOT_INC) \
            -std=gnu17 \
            -E -dM -Wno-\#warnings \