div fixes

- Makefile: don't produce unknown targets
- libtcc.c: tcc_set_linker(): improve parser
- tcc.h: tcc_internal_error(): don't record __FILE__ (for privacy reasons)
- tccgen.c:
  - reject pointer + float operation
  - use 'int level' for builtin_frame/return_address
  - save_regs(): remove VT_ARRAY (confuses riscv64-gen)
- tccpe.c: store just basename of loaded dlls (rather than full path)
- tccpp.c: remove unused TAL defines
- *-link.c: add missing ST_FUNC
- i386-gen.c: fix thiscall
- riscv64-asm.c/arm-asm.c: stay simple C89
  - avoid .designators, decl after statement
  - avoid multiple instances of same static const objects
  - use skip() instead of next() & expect()
  - use cstr_printf() instead of snprintf() & cstr_cat()
  - tcc_error(), expect(): never return

i386-link.c

@@ -25,7 +25,7 @@
 #ifdef NEED_RELOC_TYPE
 /* Returns 1 for a code relocation, 0 for a data relocation. For unknown
    relocations, returns -1. */
-int code_reloc (int reloc_type)
+ST_FUNC int code_reloc (int reloc_type)
 {
     switch (reloc_type) {
 	case R_386_RELATIVE:
@@ -55,7 +55,7 @@ int code_reloc (int reloc_type)
 /* Returns an enumerator to describe whether and when the relocation needs a
    GOT and/or PLT entry to be created. See tcc.h for a description of the
    different values. */
-int gotplt_entry_type (int reloc_type)
+ST_FUNC int gotplt_entry_type (int reloc_type)
 {
     switch (reloc_type) {
 	case R_386_RELATIVE:
@@ -171,7 +171,7 @@ ST_FUNC void relocate_plt(TCCState *s1)
 #endif
 #endif
 
-void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr, addr_t addr, addr_t val)
+ST_FUNC void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr, addr_t addr, addr_t val)
 {
     int sym_index, esym_index;