fix: move non-function declarations from .c files to *.internals.h headers (#84)

* Initial plan
* Move non-function declarations to *.internals.h headers
* Clean up whitespace in wrappers.c
Removed unnecessary empty lines in wrappers.c
* Apply review suggestions to rtdbparse.internals.h
---------
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Seunghoon Lee <lshqqytiger@naver.com>

Author: Copilot

hhss/c/rtdbparse.c

@@ -1,10 +1,6 @@
 #include "rtdbparse.h"
 #include "rtdbparse.internals.h"
 
-#include <setjmp.h>
-
-static jmp_buf env;
-
 extern array_t *rtdbparse(array_t *linestr) {
    array_t *table, *sectarr;
    char *sectname;

hhss/c/rtdbparse.internals.h

@@ -5,6 +5,7 @@
  * INCLUDES *
  ************/
 #include <ctype.h>
+#include <setjmp.h>
 #include <stdlib.h>
 #include <string.h>
 #
@@ -41,6 +42,8 @@ static void synerr(void);
  ********************/
 static const char *whitespaces = " \a\b\t\n\v\f\r";
 
+static jmp_buf env;
+
 static array_t *ls;
 static line_t *l;
 static size_t idx, len;

lib/readline.c

@@ -1,8 +1,6 @@
 #include "readline.h"
 #include "readline.internals.h"
 
-static const char *errmsg = "unable to read";
-
 extern int readln(FILE *fp, char **line, size_t *len) {
    int ch;
    size_t pos, bufsiz;

lib/readline.internals.h

@@ -12,4 +12,9 @@
  **********/
 #define READLINE_UNIT 64
 
+/********************
+ * STATIC VARIABLES *
+ ********************/
+static const char *errmsg = "unable to read";
+
 #endif

lib/wrappers.c

@@ -23,8 +23,6 @@ extern void safe_fputs(FILE *stream, const char *line) {
 /************
  * stdlib.h *
  ************/
-static const char *realloc_errmsg = "realloc error";
-
 extern void *safe_malloc(size_t siz) {
    void *ret = malloc(siz);
    if (!ret) ERR("malloc error");
@@ -66,8 +64,6 @@ extern void *safe_realloc2x_arr(void *orig_arr, size_t *cnt, size_t esiz) {
 /************
  * stdarg.h *
  ************/
-static const char *vfprintf_errmsg = "vfprintf error";
-
 extern void safe_fprintf(FILE *stream, const char *format, ...) {
    va_list ap;
    int ret;

lib/wrappers.internals.h

@@ -9,4 +9,10 @@
 #
 #include "fatal.h"
 
+/********************
+ * STATIC VARIABLES *
+ ********************/
+static const char *realloc_errmsg = "realloc error";
+static const char *vfprintf_errmsg = "vfprintf error";
+
 #endif