move unit tests into each file (compile with -DUNITTEST)

textcode/scan_base64.c

@@ -50,5 +50,6 @@ int main() {
   memset(buf,0,10); assert(scan_base64("Zm5vcmQ=",buf,&l)==8 && l==5 && !memcmp(buf,"fnord",6));
   memset(buf,0,10); assert(scan_base64("Zm5vcmQ",buf,&l)==7 && l==5 && !memcmp(buf,"fnord",6));
   memset(buf,0,10); assert(scan_base64("//8=",buf,&l)==4 && l==2 && !memcmp(buf,"\xff\xff",3));
+  return 0;
 }
 #endif

textcode/scan_jsonescape.c

@@ -101,5 +101,6 @@ int main() {
   assert(scan_jsonescape("a\\ud834\\udd1eb",buf,&l)==14 && l==6 && !memcmp(buf,"a\xf0\x9d\x84\x9e""b",6));
   /* how about some incorrect UTF-8? */
   assert(scan_jsonescape("a\xc0\xaf",buf,&l)==1 && l==1 && !memcmp(buf,"a",1));
+  return 0;
 }
 #endif

textcode/scan_uuencoded.c

@@ -36,6 +36,7 @@ int main() {
   assert(scan_uuencoded("&9FYO<F0*",buf,&i)==9 && i==6 && !memcmp(buf,"fnord\n",7));
   memset(buf,0,100);
   assert(scan_uuencoded("%9FYO<F0`",buf,&i)==9 && i==5 && !memcmp(buf,"fnord",6));
+  return 0;
 }
 
 #endif