[libc] Disable fma and fmaf for x86_64.

The version of clang installed on the buildbot workers is not able to
compile them. However, the version of gcc installed is able to compile
them fine. So, this change disables them until we can find a way to
compile them using clang on the buildbot workers.

Author: Siva Chandra Reddy

libc/config/linux/x86_64/entrypoints.txt

@@ -77,8 +77,12 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.floor
     libc.src.math.floorf
     libc.src.math.floorl
-    libc.src.math.fma
-    libc.src.math.fmaf
+    # Temporarily disable fma as the clang version
+    # on the bots cannot compile them. Note however
+    # that the version of gcc on the bots is able to
+    # compile them.
+    # libc.src.math.fma
+    # libc.src.math.fmaf
     libc.src.math.fmin
     libc.src.math.fminf
     libc.src.math.fminl