style: Add void to function without arguments

After run `make CC=clang` we found the following problems:

    error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]

Signed-off-by: Johnny Richard <johnny@johnnyrichard.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/pipac.c b/src/pipac.c
index a0031a5..b31b8b5 100644
--- a/src/pipac.c
+++ b/src/pipac.c
@@ -33,7 +33,7 @@ generate_gas_x86_64_linux(ast_node_t *func)
 }
 
 static void
-print_usage()
+print_usage(void)
 {
   fputs("pipac <filename.pipa>\n", stderr);
 }