libbacktrace patch committed: Suggest -g if no debug info

[Ian Lance Taylor]

This small libbacktrace patch suggests compiling with -g (and, on
macOS, running dsymutil), if there is no debug info.  Ran libbacktrace
testsuite.  Committed to mainline.

Ian

            * elf.c (elf_nodebug): Suggest -g.
            * macho.c (macho_nodebug): Suggest -g and dsymutil.
            * pecoff.c (coff_nodebug): Suggest -g.

b96789abf8a51e8f70309799b5dfee36d4fb3da6
diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c
index 735f8752500..e6a66c0db90 100644
--- a/libbacktrace/elf.c
+++ b/libbacktrace/elf.c
@@ -589,7 +589,7 @@ elf_nodebug (struct backtrace_state *state, uintptr_t pc,
       return bdata.ret;
     }
 
-  error_callback (data, "no debug info in ELF executable", -1);
+  error_callback (data, "no debug info in ELF executable (make sure to compile 
with -g)", -1);
   return 0;
 }
 
diff --git a/libbacktrace/macho.c b/libbacktrace/macho.c
index 42f24721e6a..5ceff05b29a 100644
--- a/libbacktrace/macho.c
+++ b/libbacktrace/macho.c
@@ -324,7 +324,7 @@ macho_nodebug (struct backtrace_state *state 
ATTRIBUTE_UNUSED,
               backtrace_full_callback callback ATTRIBUTE_UNUSED,
               backtrace_error_callback error_callback, void *data)
 {
-  error_callback (data, "no debug info in Mach-O executable", -1);
+  error_callback (data, "no debug info in Mach-O executable (make sure to 
compile with -g; may need to run dsymutil)", -1);
   return 0;
 }
 
diff --git a/libbacktrace/pecoff.c b/libbacktrace/pecoff.c
index bbb59e26d7a..e88e4d2b038 100644
--- a/libbacktrace/pecoff.c
+++ b/libbacktrace/pecoff.c
@@ -240,7 +240,7 @@ coff_nodebug (struct backtrace_state *state 
ATTRIBUTE_UNUSED,
              backtrace_full_callback callback ATTRIBUTE_UNUSED,
              backtrace_error_callback error_callback, void *data)
 {
-  error_callback (data, "no debug info in PE/COFF executable", -1);
+  error_callback (data, "no debug info in PE/COFF executable (make sure to 
compile with -g)", -1);
   return 0;
 }