[RFA 2/3] PR gdb/20653 - small cleanup in string_to_explicit_location

[Tom Tromey <tom@tromey.com>]

This bug points out that string_to_explicit_location compares a char*
against '\0'; whereas comparing against NULL is more normal.

2016-10-03  Tom Tromey  <tom@tromey.com>

	PR breakpoints/20653:
	* location.c (string_to_explicit_location): Use NULL, not '\0'.
---
 gdb/ChangeLog  | 5 +++++
 gdb/location.c | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 434f750..7a7ba1c 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2016-10-03  Tom Tromey  <tom@tromey.com>
 
+	PR breakpoints/20653:
+	* location.c (string_to_explicit_location): Use NULL, not '\0'.
+
+2016-10-03  Tom Tromey  <tom@tromey.com>
+
 	PR symtab/20652:
 	* psymtab.c (psymbol_compare): Correctly compare "ginfo.value"
 	fields.
diff --git a/gdb/location.c b/gdb/location.c
index 65116c7..8dce21a 100644
--- a/gdb/location.c
+++ b/gdb/location.c
@@ -524,7 +524,7 @@ string_to_explicit_location (const char **argp,
      character is an explicit location.  "-p" is reserved, though,
      for probe locations.  */
   if (argp == NULL
-      || *argp == '\0'
+      || *argp == NULL
       || *argp[0] != '-'
       || !isalpha ((*argp)[1])
       || ((*argp)[0] == '-' && (*argp)[1] == 'p'))
-- 
2.7.4