Fix floatscan no long double usage (#21)

* fix long double using in floatscan

* define separate macroses for copysignl, fmodl, and scalbnl instead of #ifndef

libc-top-half/headers/private/printscan.h

@@ -37,6 +37,12 @@ typedef double long_double;
 #define LDBL_MAX_10_EXP DBL_MAX_10_EXP
 #undef frexpl
 #define frexpl(x, exp) frexp(x, exp)
+#undef copysignl
+#define copysignl(x, y) copysign(x, y)
+#undef fmodl
+#define fmodl(x, y) fmod(x, y)
+#undef scalbnl
+#define scalbnl(arg, exp) scalbn(arg, exp)
 __attribute__((__cold__, __noreturn__))
 static void long_double_not_supported(void) {
     void abort(void) __attribute__((__noreturn__));

libc-top-half/musl/src/internal/floatscan.c

@@ -287,7 +287,11 @@ static long double decfloat(FILE *f, int c, int bits, int emin, int sign, int po
 	/* Assemble desired bits into floating point variable */
 	for (y=i=0; i<LD_B1B_DIG; i++) {
 		if ((a+i & MASK)==z) x[(z=(z+1 & MASK))-1] = 0;
+#if defined(__wasilibc_printscan_no_long_double)
+		y = 1000000000.0 * y + x[a+i & MASK];
+#else
 		y = 1000000000.0L * y + x[a+i & MASK];
+#endif
 	}
 
 	y *= sign;