Simplify replacement code for strtof.

strtof() is in C99 and all targeted systems have it.  We can remove the
configure probe and some dead code, but we still need replacement code
for a couple of systems that have known buggy implementations selected
via platform template.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/152683.1659830125%40sss.pgh.pa.us

src/include/pg_config.h.in

@@ -460,9 +460,6 @@
 /* Define to 1 if you have the `strsignal' function. */
 #undef HAVE_STRSIGNAL
 
-/* Define to 1 if you have the `strtof' function. */
-#undef HAVE_STRTOF
-
 /* Define to 1 if the system has the type `struct addrinfo'. */
 #undef HAVE_STRUCT_ADDRINFO
 

src/include/port.h

@@ -387,10 +387,6 @@ extern int	getpeereid(int sock, uid_t *uid, gid_t *gid);
 extern void explicit_bzero(void *buf, size_t len);
 #endif
 
-#ifndef HAVE_STRTOF
-extern float strtof(const char *nptr, char **endptr);
-#endif
-
 #ifdef HAVE_BUGGY_STRTOF
 extern float pg_strtof(const char *nptr, char **endptr);
 #define strtof(a,b) (pg_strtof((a),(b)))

src/port/strtof.c

@@ -16,43 +16,7 @@
 #include <float.h>
 #include <math.h>
 
-#ifndef HAVE_STRTOF
-/*
- * strtof() is part of C99; this version is only for the benefit of obsolete
- * platforms. As such, it is known to return incorrect values for edge cases,
- * which have to be allowed for in variant files for regression test results
- * for any such platform.
- */
 
-float
-strtof(const char *nptr, char **endptr)
-{
-	int			caller_errno = errno;
-	double		dresult;
-	float		fresult;
-
-	errno = 0;
-	dresult = strtod(nptr, endptr);
-	fresult = (float) dresult;
-
-	if (errno == 0)
-	{
-		/*
-		 * Value might be in-range for double but not float.
-		 */
-		if (dresult != 0 && fresult == 0)
-			caller_errno = ERANGE;	/* underflow */
-		if (!isinf(dresult) && isinf(fresult))
-			caller_errno = ERANGE;	/* overflow */
-	}
-	else
-		caller_errno = errno;
-
-	errno = caller_errno;
-	return fresult;
-}
-
-#elif HAVE_BUGGY_STRTOF
 /*
  * Cygwin has a strtof() which is literally just (float)strtod(), which means
  * we can't avoid the double-rounding problem; but using this wrapper does get
@@ -119,5 +83,3 @@ pg_strtof(const char *nptr, char **endptr)
 		}
 	}
 }
-
-#endif

src/tools/msvc/Solution.pm

@@ -349,7 +349,6 @@ sub GenerateFiles
 		HAVE_STRLCPY                             => undef,
 		HAVE_STRNLEN                             => 1,
 		HAVE_STRSIGNAL                           => undef,
-		HAVE_STRTOF                              => 1,
 		HAVE_STRUCT_ADDRINFO                     => 1,
 		HAVE_STRUCT_CMSGCRED                     => undef,
 		HAVE_STRUCT_OPTION                       => undef,