ctype: test and fix character conversion functions (DONE)

Some shenanigans with the scope of variables in block expressions.

STATUS

@@ -32,7 +32,7 @@ DONE:       Function/symbol/macro is defined, builds, links, and is tested
 
 7.4 <ctype.h>
     7.4.1 is*: DONE
-    7.4.2 to*: TEST
+    7.4.2 to*: DONE
 
 7.5 <errno.h>
     7.5.2 EDOM EILSEQ ERANGE: DONE

include/ctype.h

@@ -94,13 +94,13 @@ extern int toupper(int c);
 })
 
 #define tolower(c) ({ \
-	int __c = (c); \
-	isupper(__c) ? (__c | 0x20) : __c; \
+	int __c0 = (c); \
+	isupper(__c0) ? (__c0 | 0x20) : __c0; \
 })
 
 #define toupper(c) ({ \
-	int __c = (c); \
-	islower(__c) ? (__c & 0xdf) : __c; \
+	int __c0 = (c); \
+	islower(__c0) ? (__c0 & 0xdf) : __c0; \
 })
 
 #endif /*__CTYPE_H__*/