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/armeabi.c

@@ -19,7 +19,19 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.*/
 
+#ifdef __TINYC__
+#define INT_MIN (-2147483647 - 1)
+#define INT_MAX 2147483647
+#define UINT_MAX 0xffffffff
+#define LONG_MIN (-2147483647L - 1)
+#define LONG_MAX 2147483647L
+#define ULONG_MAX 0xffffffffUL
+#define LLONG_MAX 9223372036854775807LL
+#define LLONG_MIN (-9223372036854775807LL - 1)
+#define ULLONG_MAX 0xffffffffffffffffULL
+#else
 #include <limits.h>
+#endif
 
 /* We rely on the little endianness and EABI calling convention for this to
    work */