Build: Add option USE_IMPORTC=0 to switch back to compiling zlib with…

… C compiler

Wrt. Bugzilla Issue 24389.

Makefile

@@ -78,6 +78,9 @@ else
     override PIC:=
 endif
 
+# default to compiling the C parts (zlib) with DMD via importC; override with USE_IMPORTC=1/0
+USE_IMPORTC:=1
+
 # Configurable stuff that's rarely edited
 INSTALL_DIR = ../install
 DRUNTIME_PATH = $(DMD_DIR)/druntime
@@ -110,18 +113,41 @@ else
 	RUN =
 endif
 
-# Set extra CFLAGS (for DMD - the zlib .c files are compiled via importC)
-NODEFAULTLIB=-defaultlib= -debuglib=
-CFLAGS=-P=-Ietc/c/zlib
+# Set NODEFAULTLIB and CPPFLAGS (for the C preprocessor)
+NODEFAULTLIB:=-defaultlib= -debuglib=
+CPPFLAGS:=
 ifeq (,$(findstring win,$(OS)))
-	CFLAGS += -P=-DHAVE_UNISTD_H
+	CPPFLAGS := -DHAVE_UNISTD_H
 # Bundled with the system library on OSX, and doesn't work with >= MacOS 11
 	ifneq (osx,$(OS))
 		NODEFAULTLIB += -L-lpthread -L-lm
 	endif
 else
 	ifeq ($(MODEL),32omf)
-		CFLAGS += -P=-DNO_snprintf
+		CPPFLAGS := -DNO_snprintf
+	endif
+endif
+
+# Set CC, CC_OUTFILEFLAG and CFLAGS unless using importC
+ifneq ($(USE_IMPORTC),1)
+	CC := cc
+	CC_OUTFILEFLAG := -o
+
+	ifeq ($(OS),win32wine)
+		CC := wine dmc.exe
+		CFLAGS := $(if $(findstring $(BUILD),debug),-g,-O)
+	else ifeq ($(MODEL),32omf)
+		CC := dmc
+		CFLAGS := $(if $(findstring $(BUILD),debug),-g,-O)
+	else ifeq ($(OS),windows)
+		CC := cl
+		CC_OUTFILEFLAG := /Fo
+		CFLAGS := /nologo /Zl /GS- $(if $(findstring $(BUILD),debug),/Z7,/O2)
+	else # Posix
+		CFLAGS := $(MODEL_FLAG) -fPIC -std=c11 $(if $(findstring $(BUILD),debug),-g,-O3)
+		ifeq (osx64,$(OS)$(MODEL))
+			CFLAGS += --target=x86_64-darwin-apple  # ARM cpu is not supported by dmd
+		endif
 	endif
 endif
 
@@ -268,16 +294,15 @@ ALL_D_FILES = $(addsuffix .d, $(STD_MODULES) $(EXTRA_MODULES_COMMON) \
   $(EXTRA_MODULES_WIN32) $(EXTRA_MODULES_INTERNAL))
 
 # C files to be part of the build
-C_MODULES = $(addprefix etc/c/zlib/, adler32 compress crc32 deflate	\
-	gzclose gzlib gzread gzwrite infback inffast inflate inftrees trees uncompr zutil)
-
-OBJS = $(ROOT)/zlib$(DOTOBJ)
-
-# C files to be part of the build
-C_MODULES = $(addprefix etc/c/zlib/, adler32 compress crc32 deflate	\
+C_MODULES := $(addprefix etc/c/zlib/, adler32 compress crc32 deflate	\
 	gzclose gzlib gzread gzwrite infback inffast inflate inftrees trees uncompr zutil)
+C_FILES := $(addsuffix .c, $(C_MODULES))
 
-C_FILES = $(addsuffix .c, $(C_MODULES))
+ifeq ($(USE_IMPORTC),1)
+    C_OBJS := $(ROOT)/zlib$(DOTOBJ)
+else
+    C_OBJS := $(addprefix $(ROOT)/, $(addsuffix $(DOTOBJ), $(C_MODULES)))
+endif
 
 # build with shared library support (defaults to true on supported platforms)
 SHARED=$(if $(findstring $(OS),linux freebsd),1,)
@@ -323,12 +348,18 @@ endif
 lib: $(LIB)
 dll: $(ROOT)/libphobos2.so
 
-# compile zlib .c files via importC; the druntime dependency makes sure DMD has been built
+ifeq ($(USE_IMPORTC),1)
+# the druntime dependency makes sure DMD has been built
 $(ROOT)/zlib$(DOTOBJ): $(C_FILES) $(DRUNTIME)
-	$(DMD) -c $(DFLAGS) $(CFLAGS) -of$@ $(C_FILES)
+	$(DMD) -c $(DFLAGS) $(addprefix -P=,$(CPPFLAGS) -Ietc/c/zlib) -of$@ $(C_FILES)
+else
+$(ROOT)/%$(DOTOBJ): %.c
+	@[ -d $(dir $@) ] || mkdir -p $(dir $@) || [ -d $(dir $@) ]
+	$(CC) -c $(CFLAGS) $(CPPFLAGS) $< $(CC_OUTFILEFLAG)$@
+endif
 
-$(LIB): $(ROOT)/zlib$(DOTOBJ) $(ALL_D_FILES) $(DRUNTIME)
-	$(DMD) $(DFLAGS) -lib -of$@ $(DRUNTIME) $(D_FILES) $(OBJS)
+$(LIB): $(C_OBJS) $(ALL_D_FILES) $(DRUNTIME)
+	$(DMD) $(DFLAGS) -lib -of$@ $(DRUNTIME) $(D_FILES) $(C_OBJS)
 
 $(ROOT)/libphobos2.so: $(ROOT)/$(SONAME)
 	ln -sf $(notdir $(LIBSO)) $@
@@ -337,8 +368,8 @@ $(ROOT)/$(SONAME): $(LIBSO)
 	ln -sf $(notdir $(LIBSO)) $@
 
 $(LIBSO): override PIC:=-fPIC
-$(LIBSO): $(OBJS) $(ALL_D_FILES) $(DRUNTIMESO)
-	$(DMD) $(DFLAGS) -shared $(NODEFAULTLIB) -of$@ -L-soname=$(SONAME) $(DRUNTIMESO) $(LINKDL) $(D_FILES) $(OBJS)
+$(LIBSO): $(C_OBJS) $(ALL_D_FILES) $(DRUNTIMESO)
+	$(DMD) $(DFLAGS) -shared $(NODEFAULTLIB) -of$@ -L-soname=$(SONAME) $(DRUNTIMESO) $(LINKDL) $(D_FILES) $(C_OBJS)
 
 ifeq (osx,$(OS))
 # Build fat library that combines the 32 bit and the 64 bit libraries
@@ -379,8 +410,8 @@ ifneq (1,$(SHARED))
 
 $(UT_D_OBJS): $(DRUNTIME)
 
-$(ROOT)/unittest/test_runner$(DOTEXE): $(DRUNTIME_PATH)/src/test_runner.d $(UT_D_OBJS) $(OBJS) $(DRUNTIME)
-	$(DMD) $(DFLAGS) $(UDFLAGS) -of$@ $(DRUNTIME_PATH)/src/test_runner.d $(UT_D_OBJS) $(OBJS) $(DRUNTIME) $(LINKDL) $(NODEFAULTLIB)
+$(ROOT)/unittest/test_runner$(DOTEXE): $(DRUNTIME_PATH)/src/test_runner.d $(UT_D_OBJS) $(C_OBJS) $(DRUNTIME)
+	$(DMD) $(DFLAGS) $(UDFLAGS) -of$@ $(DRUNTIME_PATH)/src/test_runner.d $(UT_D_OBJS) $(C_OBJS) $(DRUNTIME) $(LINKDL) $(NODEFAULTLIB)
 
 else
 
@@ -389,8 +420,8 @@ UT_LIBSO:=$(ROOT)/unittest/libphobos2-ut.so
 $(UT_D_OBJS): $(DRUNTIMESO)
 
 $(UT_LIBSO): override PIC:=-fPIC
-$(UT_LIBSO): $(UT_D_OBJS) $(OBJS) $(DRUNTIMESO)
-	$(DMD) $(DFLAGS) -shared $(UDFLAGS) -of$@ $(UT_D_OBJS) $(OBJS) $(DRUNTIMESO) $(LINKDL) $(NODEFAULTLIB)
+$(UT_LIBSO): $(UT_D_OBJS) $(C_OBJS) $(DRUNTIMESO)
+	$(DMD) $(DFLAGS) -shared $(UDFLAGS) -of$@ $(UT_D_OBJS) $(C_OBJS) $(DRUNTIMESO) $(LINKDL) $(NODEFAULTLIB)
 
 $(ROOT)/unittest/test_runner$(DOTEXE): $(DRUNTIME_PATH)/src/test_runner.d $(UT_LIBSO)
 	$(DMD) $(DFLAGS) -of$@ $< -L$(UT_LIBSO) $(NODEFAULTLIB)