libc: centralize a few numeric symbols

fabs, __infinity, and __nan are universally implemented so declare them
in gen/Symbol.map.

We would also include __flt_rounds, but  it's under FBSD_1.3 on arm so
until that's gone we're stuck with it.  Likewise, everyone but i386
implements fp[gs]etmask.

Reviewed by:	imp, kib, emaste
Differential Revision:	https://reviews.freebsd.org/D42618

lib/libc/aarch64/Symbol.map

@@ -5,10 +5,7 @@
  */
 FBSD_1.0 {
 	.mcount;
-	fabs;
 	__flt_rounds;
 	fpgetmask;
 	fpsetmask;
-	__infinity;
-	__nan;
 };

lib/libc/amd64/Symbol.map

@@ -5,7 +5,6 @@
  */
 FBSD_1.0 {
 	.mcount;
-	fabs;
 	__flt_rounds;
 	fpgetmask;
 	fpgetprec;
@@ -14,8 +13,6 @@ FBSD_1.0 {
 	fpsetmask;
 	fpsetprec;
 	fpsetround;
-	__infinity;
-	__nan;
 	rfork_thread;
 	amd64_get_fsbase;
 	amd64_get_gsbase;

lib/libc/arm/Symbol.map

@@ -6,9 +6,6 @@
 FBSD_1.0 {
 	__mcount;
 	alloca;
-	fabs;
-	__infinity;
-	__nan;
 	brk;
 	sbrk;
 };

lib/libc/gen/Symbol.map

@@ -107,6 +107,7 @@ FBSD_1.0 {
 	execv;
 	execvp;
 	execvP;
+	fabs;
 	fmtcheck;
 	fmtmsg;
 	fnmatch;
@@ -181,10 +182,12 @@ FBSD_1.0 {
 	endusershell;
 	setusershell;
 	getvfsbyname;
+	__nan;
 	__isnan;
 	isnan;
 	__isnanf;
 	isnanf;
+	__infinity;
 	__isinf;
 	isinf;
 	__isinff;

lib/libc/i386/Symbol.map

@@ -6,10 +6,7 @@
 FBSD_1.0 {
 	.mcount;
 	alloca;
-	fabs;
 	__flt_rounds;
-	__nan;
-	__infinity;
 	rfork_thread;
 	brk;
 	i386_clr_watch;

lib/libc/powerpc/Symbol.map

@@ -5,15 +5,12 @@
  */
 FBSD_1.0 {
 	_mcount;
-	fabs;
 	__flt_rounds;
 	fpgetmask;
 	fpgetround;
 	fpgetsticky;
 	fpsetmask;
 	fpsetround;
-	__infinity;
-	__nan;
 	brk;
 	sbrk;
 };

lib/libc/powerpc64/Symbol.map

@@ -5,15 +5,12 @@
  */
 FBSD_1.0 {
 	_mcount;
-	fabs;
 	__flt_rounds;
 	fpgetmask;
 	fpgetround;
 	fpgetsticky;
 	fpsetmask;
 	fpsetround;
-	__infinity;
-	__nan;
 	brk;
 	sbrk;
 };

lib/libc/riscv/Symbol.map

@@ -4,10 +4,7 @@
  * stdlib/Symbol.map, string/Symbol.map, sys/Symbol.map, ...).
  */
 FBSD_1.0 {
-	fabs;
 	__flt_rounds;
 	fpgetmask;
 	fpsetmask;
-	__infinity;
-	__nan;
 };