honor no_quiet for missing llvm_mode output, also print to stderr with afl-*-rt.o.c instead of stdout for errors plus two potential bad free() fixes

gcc_plugin/Makefile

@@ -30,6 +30,7 @@ CFLAGS      ?= -O3 -g -funroll-loops
 CFLAGS      += -Wall -I../include -D_FORTIFY_SOURCE=2 -Wno-pointer-sign \
                -DAFL_PATH=\"$(HELPER_PATH)\" -DBIN_PATH=\"$(BIN_PATH)\" \
                -DGCC_VERSION=\"$(GCCVER)\" -DGCC_BINDIR=\"$(GCCBINDIR)\" \
+               -Wno-unused-function
 
 CXXFLAGS    ?= -O3 -g -funroll-loops
 CXXEFLAGS   := $(CXXFLAGS) -Wall -D_FORTIFY_SOURCE=2

gcc_plugin/afl-gcc-fast.c

@@ -361,7 +361,9 @@ int main(int argc, char** argv, char** envp) {
 
     }
 
-  }
+  } else
+
+    be_quiet = 1;
 
   check_environment_vars(envp);
 

gcc_plugin/afl-gcc-rt.o.c

@@ -94,7 +94,7 @@ static void __afl_map_shm(void) {
     shm_fd = shm_open(shm_file_path, O_RDWR, 0600);
     if (shm_fd == -1) {
 
-      printf("shm_open() failed\n");
+      fprintf(stderr, "shm_open() failed\n");
       exit(1);
 
     }
@@ -106,7 +106,7 @@ static void __afl_map_shm(void) {
       close(shm_fd);
       shm_fd = -1;
 
-      printf("mmap() failed\n");
+      fprintf(stderr, "mmap() failed\n");
       exit(2);
 
     }