add inline isspace in ctype.h as an optimization

isspace can be a bottleneck in a simple parser, inlining it
gives slightly smaller and faster code

src/locale/pleval.o already had this optimization, the size
change for other libc functions for i386 is

src/internal/intscan.o     2134    2118   -16
src/locale/dcngettext.o    1562    1552   -10
src/network/res_msend.o    1961    1940   -21
src/network/lookup_name.o  2627    2608   -19
src/network/getnameinfo.o  1814    1811    -3
src/network/lookup_serv.o   643     624   -19
src/stdio/vfscanf.o        2675    2663   -12
src/stdlib/atoll.o          117     107   -10
src/stdlib/atoi.o            95      91    -4
src/stdlib/atol.o            95      91    -4
src/time/strptime.o        1515    1503   -12
(TOTALS)                 432451  432321  -130

include/ctype.h

@@ -22,13 +22,18 @@ int   isxdigit(int);
 int   tolower(int);
 int   toupper(int);
 
+static __inline int __isspace(int _c)
+{
+	return _c == ' ' || (unsigned)_c-'\t' < 5;
+}
+
 #define isalpha(a) ((((unsigned)(a)|32)-'a') < 26)
 #define isdigit(a) (((unsigned)(a)-'0') < 10)
 #define islower(a) (((unsigned)(a)-'a') < 26)
 #define isupper(a) (((unsigned)(a)-'A') < 26)
 #define isprint(a) (((unsigned)(a)-0x20) < 0x5f)
 #define isgraph(a) (((unsigned)(a)-0x21) < 0x5e)
-
+#define isspace(a) __isspace(a)
 
 
 #if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \

src/ctype/isspace.c

@@ -1,5 +1,6 @@
 #include <ctype.h>
 #include "libc.h"
+#undef isspace
 
 int isspace(int c)
 {

src/locale/pleval.c

@@ -28,14 +28,6 @@ struct st {
 	int op;
 };
 
-/* TODO: this should go into ctypes.h */
-#undef isspace
-#define isspace(a) __isspace(a)
-static __inline int __isspace(int _c)
-{
-	return _c == ' ' || (unsigned)_c-'\t' < 5;
-}
-
 static const char *skipspace(const char *s)
 {
 	while (isspace(*s)) s++;