Fix a problem where libm compiled under 5.X would depend on features

that are only in libc.so.5.  This broke some 4.X applications linked
to libm and run under 5.X.

Background:
In C99, isinf() and isnan() cannot be implemented as regular
functions.  We use macros that call libc functions in 5.X, but for
libm-internal use, we need to use the old versions until the next
time libm's major version number is bumped.

Submitted by:	bde
Reported by:	imp, kris

2 files changed, 8 insertions, 2 deletions

diff --git a/lib/msun/src/e_scalb.c b/lib/msun/src/e_scalb.c
index 5b66be5..cc35d17 100644
--- a/lib/msun/src/e_scalb.c
+++ b/lib/msun/src/e_scalb.c
@@ -23,6 +23,9 @@ static char rcsid[] = "$FreeBSD$";
 #include "math.h"
 #include "math_private.h"
 
+/* XXX lost declaration of this and isinf() in math.h but still have funcs. */
+int	(isnan)(float x);
+
 #ifdef _SCALB_INT
 double
 __ieee754_scalb(double x, int fn)
@@ -34,7 +37,7 @@ __ieee754_scalb(double x, double fn)
 #ifdef _SCALB_INT
 	return scalbn(x,fn);
 #else
-	if (isnan(x)||isnan(fn)) return x*fn;
+	if ((isnan)(x)||(isnan)(fn)) return x*fn;
 	if (!finite(fn)) {
 	    if(fn>0.0) return x*fn;
 	    else       return x/(-fn);
diff --git a/lib/msun/src/e_scalbf.c b/lib/msun/src/e_scalbf.c
index 0888433..f56e077 100644
--- a/lib/msun/src/e_scalbf.c
+++ b/lib/msun/src/e_scalbf.c
@@ -20,6 +20,9 @@ static char rcsid[] = "$FreeBSD$";
 #include "math.h"
 #include "math_private.h"
 
+/* XXX lost declaration of this and isnan() in math.h but still have funcs. */
+int	(isnanf)(float x);
+
 #ifdef _SCALB_INT
 float
 __ieee754_scalbf(float x, int fn)
@@ -31,7 +34,7 @@ __ieee754_scalbf(float x, float fn)
 #ifdef _SCALB_INT
 	return scalbnf(x,fn);
 #else
-	if (isnanf(x)||isnanf(fn)) return x*fn;
+	if ((isnanf)(x)||(isnanf)(fn)) return x*fn;
 	if (!finitef(fn)) {
 	    if(fn>(float)0.0) return x*fn;
 	    else       return x/(-fn);