Warn about a conflicting compile options spectified on the command line.

Try "tcc -E -c tccasm.c -o tccasm.o"

libtcc.c

@@ -906,7 +906,7 @@ LIBTCCAPI TCCState *tcc_new(void)
 #else
     tcc_set_lib_path(s, CONFIG_TCCDIR);
 #endif
-    s->output_type = TCC_OUTPUT_MEMORY;
+    s->output_type = 0;
     preprocess_new();
     s->include_stack_ptr = s->include_stack;
 
@@ -1831,6 +1831,8 @@ PUB_FUNC int tcc_parse_args(TCCState *s, int argc, char **argv)
             s->do_debug = 1;
             break;
         case TCC_OPTION_c:
+    	    if (s->output_type)
+                tcc_warning("-c: some compiler action already specified (%d)", s->output_type);
             s->output_type = TCC_OUTPUT_OBJ;
             break;
 #ifdef TCC_TARGET_ARM
@@ -1849,6 +1851,8 @@ PUB_FUNC int tcc_parse_args(TCCState *s, int argc, char **argv)
             s->static_link = 1;
             break;
         case TCC_OPTION_shared:
+    	    if (s->output_type)
+                tcc_warning("-shared: some compiler action already specified (%d)", s->output_type);
             s->output_type = TCC_OUTPUT_DLL;
             break;
         case TCC_OPTION_soname:
@@ -1862,6 +1866,8 @@ PUB_FUNC int tcc_parse_args(TCCState *s, int argc, char **argv)
             break;
         case TCC_OPTION_r:
             /* generate a .o merging several output files */
+    	    if (s->output_type)
+                tcc_warning("-r: some compiler action already specified (%d)", s->output_type);
             s->option_r = 1;
             s->output_type = TCC_OUTPUT_OBJ;
             break;
@@ -1878,6 +1884,8 @@ PUB_FUNC int tcc_parse_args(TCCState *s, int argc, char **argv)
             s->print_search_dirs = 1;
             break;
         case TCC_OPTION_run:
+    	    if (s->output_type)
+                tcc_warning("-run: some compiler action already specified (%d)", s->output_type);
             s->output_type = TCC_OUTPUT_MEMORY;
             tcc_set_options(s, optarg);
             run = 1;
@@ -1907,6 +1915,8 @@ PUB_FUNC int tcc_parse_args(TCCState *s, int argc, char **argv)
             cstr_ccat(&linker_arg, '\0');
             break;
         case TCC_OPTION_E:
+    	    if (s->output_type)
+                tcc_warning("-E: some compiler action already specified (%d)", s->output_type);
             s->output_type = TCC_OUTPUT_PREPROCESS;
             break;
         case TCC_OPTION_MD:

libtcc.h

@@ -58,11 +58,11 @@ LIBTCCAPI int tcc_compile_string(TCCState *s, const char *buf);
 
 /* set output type. MUST BE CALLED before any compilation */
 LIBTCCAPI int tcc_set_output_type(TCCState *s, int output_type);
-#define TCC_OUTPUT_MEMORY   0 /* output will be run in memory (default) */
-#define TCC_OUTPUT_EXE      1 /* executable file */
-#define TCC_OUTPUT_DLL      2 /* dynamic library */
-#define TCC_OUTPUT_OBJ      3 /* object file */
-#define TCC_OUTPUT_PREPROCESS 4 /* only preprocess (used internally) */
+#define TCC_OUTPUT_MEMORY   1 /* output will be run in memory (default) */
+#define TCC_OUTPUT_EXE      2 /* executable file */
+#define TCC_OUTPUT_DLL      3 /* dynamic library */
+#define TCC_OUTPUT_OBJ      4 /* object file */
+#define TCC_OUTPUT_PREPROCESS 5 /* only preprocess (used internally) */
 
 /* equivalent to -Lpath option */
 LIBTCCAPI int tcc_add_library_path(TCCState *s, const char *pathname);

tcc.c

@@ -249,7 +249,6 @@ int main(int argc, char **argv)
     const char *first_file = NULL;
 
     s = tcc_new();
-    s->output_type = TCC_OUTPUT_EXE;
 
     optind = tcc_parse_args(s, argc - 1, argv + 1);
     tcc_set_environment(s);
@@ -259,6 +258,9 @@ int main(int argc, char **argv)
         return 1;
     }
 
+    if (s->output_type == 0)
+	s->output_type = TCC_OUTPUT_EXE;
+
     if (s->option_m)
         exec_other_tcc(s, argv, s->option_m);