Build LLVM with -Wstrict-prototypes enabled

Clang 5 supports -Wstrict-prototypes. We should use it to catch any C
declarations that declare a non-prototype function.

rdar://33705313

Differential Revision: https://reviews.llvm.org/D36669

llvm-svn: 312240
diff --git a/compiler-rt/lib/profile/InstrProfiling.h b/compiler-rt/lib/profile/InstrProfiling.h
index 945f1c4..a644d6a 100644
--- a/compiler-rt/lib/profile/InstrProfiling.h
+++ b/compiler-rt/lib/profile/InstrProfiling.h
@@ -63,8 +63,8 @@
 const char *__llvm_profile_end_names(void);
 uint64_t *__llvm_profile_begin_counters(void);
 uint64_t *__llvm_profile_end_counters(void);
-ValueProfNode *__llvm_profile_begin_vnodes();
-ValueProfNode *__llvm_profile_end_vnodes();
+ValueProfNode *__llvm_profile_begin_vnodes(void);
+ValueProfNode *__llvm_profile_end_vnodes(void);
 
 /*!
  * \brief Clear profile counters to zero.
@@ -164,7 +164,7 @@
  * merge mode is turned on for instrumented programs with shared libs).
  * Side-effect: this API call will invoke malloc with dynamic memory allocation.
  */
-const char *__llvm_profile_get_path_prefix();
+const char *__llvm_profile_get_path_prefix(void);
 
 /*! \brief Get the magic token for the file format. */
 uint64_t __llvm_profile_get_magic(void);