Avoid usage of LONG_BIT in signal headers.

Clang has its own limits.h which is ahead of ours on the inclusion
path. This header uses include_next to include our header, but only
in hosted mode. This means that in freestanding mode we don't get our
limits.h macro definitions, including LONG_BIT. This ends up causing
our signal.h to produce errors when included in freestanding mode on
32-bit platforms.

Fix the errors by replacing usage of LONG_BIT with (8 * sizeof(long))
in the signal headers.

Change-Id: I18ec7b6876d5f862beae09f0c011128eef97c869

libc/include/android/legacy_signal_inlines.h

diff --git a/libc/include/android/legacy_signal_inlines.h b/libc/include/android/legacy_signal_inlines.h
index 95c2320..f2bdcf6 100644
--- a/libc/include/android/legacy_signal_inlines.h
+++ b/libc/include/android/legacy_signal_inlines.h
@@ -89,7 +89,7 @@
     errno = EINVAL;
     return -1;
   }
-  return (int)((local_set[bit / LONG_BIT] >> (bit % LONG_BIT)) & 1);
+  return (int)((local_set[bit / (8 * sizeof(long))] >> (bit % (8 * sizeof(long)))) & 1);
 }
 
 static __inline int sigaddset(sigset_t *set, int signum) {
@@ -100,7 +100,7 @@
     errno = EINVAL;
     return -1;
   }
-  local_set[bit / LONG_BIT] |= 1UL << (bit % LONG_BIT);
+  local_set[bit / (8 * sizeof(long))] |= 1UL << (bit % (8 * sizeof(long)));
   return 0;
 }
 
@@ -112,7 +112,7 @@
     errno = EINVAL;
     return -1;
   }
-  local_set[bit / LONG_BIT] &= ~(1UL << (bit % LONG_BIT));
+  local_set[bit / (8 * sizeof(long))] &= ~(1UL << (bit % (8 * sizeof(long))));
   return 0;
 }
 

libc/include/bits/signal_types.h

diff --git a/libc/include/bits/signal_types.h b/libc/include/bits/signal_types.h
index e1a155f..699e257 100644
--- a/libc/include/bits/signal_types.h
+++ b/libc/include/bits/signal_types.h
@@ -61,7 +61,7 @@
 #if defined(__LP64__)
 typedef sigset_t sigset64_t;
 #else
-typedef struct { unsigned long __bits[_KERNEL__NSIG/LONG_BIT]; } sigset64_t;
+typedef struct { unsigned long __bits[_KERNEL__NSIG/(8*sizeof(long))]; } sigset64_t;
 #endif
 
 #if defined(__LP64__)