cross-compilers: allow individual configuration

since configure supports only native configuration
a file 'cross-tcc.mak' needs to be created manually.
It is included in the Makefile if present.

# ----------------------------------------------------
# Example config-cross.mak:
#
# windows -> i386-linux cross-compiler
# (it expects the linux files in <prefix>/i386-linux)

ROOT-i386 = {B}/i386-linux
CRT-i386 = $(ROOT-i386)/usr/lib
LIB-i386 = $(ROOT-i386)/lib:$(ROOT-i386)/usr/lib
INC-i386 = {B}/lib/include:$(ROOT-i386)/usr/include
DEF-i386 += -D__linux__

# ----------------------------------------------------

Also:
- use libtcc1-<target>.a instead of directories
- add dummy arm assembler
- remove include dependencies from armeabi.c/lib-arm64.c
- tccelf/ld_add_file: add SYSROOT (when defined) to absolute
  filenames coming from ld-scripts

lib/Makefile

@@ -6,34 +6,15 @@ TOP = ..
 include $(TOP)/Makefile
 VPATH = $(TOPSRC)/lib $(TOPSRC)/win32/lib
 
-ifndef TARGET
- # we're building the native libtcc1.a
- ifdef CONFIG_WIN32
-  ifeq ($(ARCH),x86_64)
-   TARGET = x86_64-win32
-  else
-   TARGET = i386-win32
-  endif
- else ifeq ($(ARCH),i386)
-  TARGET = i386
- else ifeq ($(ARCH),x86_64)
-  TARGET = x86_64
- else ifeq ($(ARCH),arm)
-  TARGET = arm
- else ifeq ($(ARCH),arm64)
-  TARGET = arm64
- endif
+ifneq ($(CROSS),yes)
+ TCC = $(TOP)/tcc$(EXESUF)
+ OUT = ../libtcc1.a
  BCHECK_O = bcheck.o
+else
+ TCC = $(TOP)/$(TARGET)-tcc$(EXESUF)
+ OUT = libtcc1-$(TARGET).a
 endif
 
-DIR = $(TARGET)
-
-native : ../libtcc1.a
-cross : $(DIR)/libtcc1.a
-
-native : TCC = $(TOP)/tcc$(EXESUF)
-cross : TCC = $(TOP)/$(TARGET)-tcc$(EXESUF)
-
 XCC = $(TCC) -B$(TOPSRC)
 XAR = $(TCC) -ar
 
@@ -41,33 +22,39 @@ I386_O = libtcc1.o alloca86.o alloca86-bt.o $(BCHECK_O)
 X86_64_O = libtcc1.o alloca86_64.o alloca86_64-bt.o $(BCHECK_O)
 ARM_O = libtcc1.o armeabi.o alloca-arm.o
 ARM64_O = lib-arm64.o
-WIN32_O = crt1.o crt1w.o wincrt1.o wincrt1w.o dllcrt1.o dllmain.o chkstk.o
+WIN_O = crt1.o crt1w.o wincrt1.o wincrt1w.o dllcrt1.o dllmain.o
 
 ifeq "$(TARGET)" "i386-win32"
- OBJ = $(addprefix $(DIR)/,$(I386_O) $(WIN32_O))
+ OBJ = $(I386_O) chkstk.o $(WIN_O)
  TGT = -DTCC_TARGET_I386 -DTCC_TARGET_PE
  XCC = $(TCC) -B$(TOPSRC)/win32 -I$(TOPSRC)/include
 else ifeq "$(TARGET)" "x86_64-win32"
- OBJ = $(addprefix $(DIR)/,$(X86_64_O) $(WIN32_O))
+ OBJ = $(X86_64_O) chkstk.o $(WIN_O)
  TGT = -DTCC_TARGET_X86_64 -DTCC_TARGET_PE
  XCC = $(TCC) -B$(TOPSRC)/win32 -I$(TOPSRC)/include
+else ifeq "$(TARGET)" "arm-wince"
+ OBJ = $(ARM_O) $(WIN_O)
+ TGT = -DTCC_TARGET_ARM -DTCC_TARGET_PE
+ XCC = $(TCC) -B$(TOPSRC)/win32 -I$(TOPSRC)/include
 else ifeq "$(TARGET)" "i386"
- OBJ = $(addprefix $(DIR)/,$(I386_O))
+ OBJ = $(I386_O)
  TGT = -DTCC_TARGET_I386
 else ifeq "$(TARGET)" "x86_64"
- OBJ = $(addprefix $(DIR)/,$(X86_64_O))
+ OBJ = $(X86_64_O)
  TGT = -DTCC_TARGET_X86_64
-else ifeq "$(TARGET)" "arm"
- OBJ = $(addprefix $(DIR)/,$(ARM_O))
+else ifeq "$(TARGET)" "arm-eabihf"
+ OBJ = $(ARM_O)
  TGT = -DTCC_TARGET_ARM
+ ifneq ($(CROSS),yes)
  # using gcc, need asm
  XCC = $(CC)
  XFLAGS = $(CFLAGS) -fPIC
  XAR = $(AR)
+ endif
 else ifeq "$(TARGET)" "arm64"
- OBJ = $(addprefix $(DIR)/,$(ARM64_O))
+ OBJ = $(ARM64_O)
  TGT = -DTCC_TARGET_ARM64
-else
+else ifneq "$(TARGET)" ""
  $(error libtcc1.a not supported on target '$(TARGET)')
 endif
 
@@ -76,21 +63,18 @@ ifeq ($(TARGETOS),Darwin)
  BCHECK_O =
 endif
 
-$(DIR)/libtcc1.a ../libtcc1.a : $(OBJ)
-	$(XAR) rcs $@ $(OBJ)
-$(DIR)/%.o : %.c
+all : $(OUT)
+
+$(OUT) : $(patsubst %.o,%-$(TARGET).o,$(OBJ))
+	$(XAR) rcs $@ $^
+%-$(TARGET).o : %.c
 	$(XCC) -c $< -o $@ $(TGT) $(XFLAGS)
-$(DIR)/%.o : %.S
+%-$(TARGET).o : %.S
 	$(XCC) -c $< -o $@ $(TGT) $(XFLAGS)
 
-$(DIR)/crt1w.o : crt1.c
-$(DIR)/wincrt1w.o : wincrt1.c
-
-$(OBJ) : $(DIR)/exists
-
-%/exists :
-	mkdir -p $(DIR)
-	@echo $@ > $@
+crt1w-$(TARGET).o : crt1.c
+wincrt1w-$(TARGET).o : wincrt1.c
+bcheck-$(TARGET).o : XFLAGS += -w
 
 clean :
-	rm -rf i386-win32 x86_64-win32 i386 x86_64 arm arm64
+	rm -f *.a *.o $(OUT)