Specialize fdlibm to jerry

Keep IEEE code paths only:
* removed SVID, XOPEN, POSIX code paths from everywhere.
* deleted s_lib_version.c, as version is only useful if multiple
  standards are supported.
* deleted k_standard.c, as it handles non-IEEE exception cases only.
* renamed the e_{acos,asin,atan2,exp,fmod,log,pow,sqrt}.c sources as
  s_.*, dropped the __ieee754_ prefix from the names of the
  appropriate functions therein, and deleted the
  w_{acos,asin,atan2,exp,fmod,log,pow,sqrt}.c wrapper code.

Keep C99 declaration variants only:
* removed old C-style function declaration variants.
* removed data declaration variants where const qualifier was not
  used.

Clean unused sources/functions:
* removed s_{rint,significand,tanh}.c and the appropriate functions
  defined therein.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

third-party/fdlibm/s_floor.c

@@ -22,18 +22,9 @@
 
 #include "fdlibm.h"
 
-#ifdef __STDC__
 static const double huge = 1.0e300;
-#else
-static double huge = 1.0e300;
-#endif
 
-#ifdef __STDC__
-	double floor(double x)
-#else
-	double floor(x)
-	double x;
-#endif
+double floor(double x)
 {
 	int i0,i1,j0;
 	unsigned i,j;
@@ -43,7 +34,7 @@ static double huge = 1.0e300;
 	if(j0<20) {
 	    if(j0<0) { 	/* raise inexact if x != 0 */
 		if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
-		    if(i0>=0) {i0=i1=0;} 
+		    if(i0>=0) {i0=i1=0;}
 		    else if(((i0&0x7fffffff)|i1)!=0)
 			{ i0=0xbff00000;i1=0;}
 		}
@@ -63,7 +54,7 @@ static double huge = 1.0e300;
 	    if((i1&i)==0) return x;	/* x is integral */
 	    if(huge+x>0.0) { 		/* raise inexact flag */
 		if(i0<0) {
-		    if(j0==20) i0+=1; 
+		    if(j0==20) i0+=1;
 		    else {
 			j = i1+(1<<(52-j0));
 			if(j<i1) i0 +=1 ; 	/* got a carry */