Remove weak reference construct from fenv code.

I grepped through the FreeBSD source tree and for me, it seems to be
totally unclear why these two specific functions are weak references.
Such a construct is commonly used by FreeBSD's threading library
(libthr) to override certain functions, but I can't find any traces of
that.

Just use the function name directly. This fixes a compiler warning as
well (-Wmissing-prototypes).

amd64/fenv.c

@@ -128,7 +128,7 @@ feupdateenv(const fenv_t *envp)
 }
 
 int
-__feenableexcept(int mask)
+feenableexcept(int mask)
 {
 	uint32_t mxcsr, omask;
 	uint16_t control;
@@ -145,7 +145,7 @@ __feenableexcept(int mask)
 }
 
 int
-__fedisableexcept(int mask)
+fedisableexcept(int mask)
 {
 	uint32_t mxcsr, omask;
 	uint16_t control;
@@ -160,6 +160,3 @@ __fedisableexcept(int mask)
 	__ldmxcsr(mxcsr);
 	return (omask);
 }
-
-__weak_reference(__feenableexcept, feenableexcept);
-__weak_reference(__fedisableexcept, fedisableexcept);

i387/fenv.c

@@ -182,7 +182,7 @@ feupdateenv(const fenv_t *envp)
 }
 
 int
-__feenableexcept(int mask)
+feenableexcept(int mask)
 {
 	uint32_t mxcsr, omask;
 	uint16_t control;
@@ -204,7 +204,7 @@ __feenableexcept(int mask)
 }
 
 int
-__fedisableexcept(int mask)
+fedisableexcept(int mask)
 {
 	uint32_t mxcsr, omask;
 	uint16_t control;
@@ -224,6 +224,3 @@ __fedisableexcept(int mask)
 	}
 	return (omask);
 }
-
-__weak_reference(__feenableexcept, feenableexcept);
-__weak_reference(__fedisableexcept, fedisableexcept);