Use less c++

As a design, it would be better if we didn't need to have a dependency
on c++ in a c library.  Moving things to C will reduce both
dependencies and compile times.

Reduced dependencies makes the library itself easier to use in
more environments.

libmctp Is a library that doesn't take a dependency on gtest for its
tests
libpldm Is an example that does take a dependency on gtest.

Change-Id: If1dc638f87b75b28181a0baf67f5a18d389cff81
Signed-off-by: Ed Tanous <etanous@nvidia.com>
diff --git a/cli-app/cper-convert.c b/cli-app/cper-convert.c
index 082e452..942d258 100644
--- a/cli-app/cper-convert.c
+++ b/cli-app/cper-convert.c
@@ -15,7 +15,7 @@
 #include <libcper/json-schema.h>
 
 void cper_to_json(char *in_file, char *out_file, int is_single_section);
-void json_to_cper(char *in_file, char *out_file);
+void json_to_cper(const char *in_file, const char *out_file);
 void print_help(void);
 
 int main(int argc, char *argv[])
@@ -128,7 +128,7 @@
 }
 
 //Command for converting a provided CPER-JSON JSON file to CPER binary.
-void json_to_cper(char *in_file, char *out_file)
+void json_to_cper(const char *in_file, const char *out_file)
 {
 	//Verify output file exists.
 	if (out_file == NULL) {