Remove __fpclassify and __signbit definitions.

With fpclassify and signbit now implemented as compiler builtins in a64f6544,
these out-of-line helper functions are no longer needed.

Makefile

@@ -140,7 +140,9 @@ LIBC_TOP_HALF_MUSL_SOURCES = \
     $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/prng/*.c) \
     $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/conf/*.c) \
     $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/ctype/*.c) \
-    $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/math/*.c) \
+    $(filter-out %/__signbit.c %/__signbitf.c %/__signbitl.c \
+                 %/__fpclassify.c %/__fpclassifyf.c %/__fpclassifyl.c, \
+                 $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/math/*.c)) \
     $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/complex/*.c) \
     $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/crypt/*.c)
 MUSL_PRINTSCAN_SOURCES = \

expected/wasm32-wasi/defined-symbols.txt

@@ -52,9 +52,6 @@ __flbf
 __floatscan
 __fmodeflags
 __fopen_rb_ca
-__fpclassify
-__fpclassifyf
-__fpclassifyl
 __fpending
 __fpurge
 __fputwc_unlocked
@@ -170,9 +167,6 @@ __secs_to_zone
 __seed48
 __shgetc
 __shlim
-__signbit
-__signbitf
-__signbitl
 __signgam
 __sin
 __sindf