Consistently use %m rather than strerror() in logging.

When I added %m to async_safe_* too, we never followed up and cleaned up
callers.

Test: treehugger
Change-Id: If81943c4c45de49f0fb4bc29cfbd3fc53d4a47fe
diff --git a/libc/bionic/pthread_attr.cpp b/libc/bionic/pthread_attr.cpp
index cdae72c..de4cc9e 100644
--- a/libc/bionic/pthread_attr.cpp
+++ b/libc/bionic/pthread_attr.cpp
@@ -158,12 +158,12 @@
 static uintptr_t __get_main_stack_startstack() {
   FILE* fp = fopen("/proc/self/stat", "re");
   if (fp == nullptr) {
-    async_safe_fatal("couldn't open /proc/self/stat: %s", strerror(errno));
+    async_safe_fatal("couldn't open /proc/self/stat: %m");
   }
 
   char line[BUFSIZ];
   if (fgets(line, sizeof(line), fp) == nullptr) {
-    async_safe_fatal("couldn't read /proc/self/stat: %s", strerror(errno));
+    async_safe_fatal("couldn't read /proc/self/stat: %m");
   }
 
   fclose(fp);
@@ -205,7 +205,7 @@
   // Hunt for the region that contains that address.
   FILE* fp = fopen("/proc/self/maps", "re");
   if (fp == nullptr) {
-    async_safe_fatal("couldn't open /proc/self/maps: %s", strerror(errno));
+    async_safe_fatal("couldn't open /proc/self/maps: %m");
   }
   char line[BUFSIZ];
   while (fgets(line, sizeof(line), fp) != nullptr) {
@@ -219,7 +219,7 @@
       }
     }
   }
-  async_safe_fatal("Stack not found in /proc/self/maps");
+  async_safe_fatal("stack not found in /proc/self/maps");
 }
 
 __BIONIC_WEAK_FOR_NATIVE_BRIDGE