Bug fix: #48: Compilation failure with old libconfig/libpcre

- Fix compilation failure with <libpcre-8.20 and <libconfig-1.4. Tested
  with libpcre-8.12 and libconfig-1.3.2, but not extensively tested.
  libconfig-1.3* probably has more limitations on configuration file
  syntax (enforces comma at the end of a setting?) and does not support
  @include.

- Make it possible to turn off PCRE and libconfig support using
  environment variable "CFG". Not well tested. CMake might provide a
  better solution.

compton.c

@@ -3071,7 +3071,7 @@ open_config_file(char *cpath, char **ppath) {
  */
 static void
 parse_config(char *cpath, struct options_tmp *pcfgtmp) {
-  char *path = NULL, *parent = NULL;
+  char *path = NULL;
   FILE *f;
   config_t cfg;
   int ival = 0;
@@ -3085,9 +3085,11 @@ parse_config(char *cpath, struct options_tmp *pcfgtmp) {
   }
 
   config_init(&cfg);
-  parent = dirname(path);
+#ifndef CONFIG_LIBCONFIG_LEGACY
+  char *parent = dirname(path);
   if (parent)
     config_set_include_dir(&cfg, parent);
+#endif
 
   if (CONFIG_FALSE == config_read(&cfg, f)) {
     printf("Error when reading configuration file \"%s\", line %d: %s\n",
@@ -3104,7 +3106,7 @@ parse_config(char *cpath, struct options_tmp *pcfgtmp) {
   // right now. It will be done later
 
   // -D (fade_delta)
-  if (config_lookup_int(&cfg, "fade-delta", &ival))
+  if (lcfg_lookup_int(&cfg, "fade-delta", &ival))
     opts.fade_delta = ival;
   // -I (fade_in_step)
   if (config_lookup_float(&cfg, "fade-in-step", &dval))
@@ -3113,13 +3115,13 @@ parse_config(char *cpath, struct options_tmp *pcfgtmp) {
   if (config_lookup_float(&cfg, "fade-out-step", &dval))
     opts.fade_out_step = normalize_d(dval) * OPAQUE;
   // -r (shadow_radius)
-  config_lookup_int(&cfg, "shadow-radius", &opts.shadow_radius);
+  lcfg_lookup_int(&cfg, "shadow-radius", &opts.shadow_radius);
   // -o (shadow_opacity)
   config_lookup_float(&cfg, "shadow-opacity", &opts.shadow_opacity);
   // -l (shadow_offset_x)
-  config_lookup_int(&cfg, "shadow-offset-x", &opts.shadow_offset_x);
+  lcfg_lookup_int(&cfg, "shadow-offset-x", &opts.shadow_offset_x);
   // -t (shadow_offset_y)
-  config_lookup_int(&cfg, "shadow-offset-y", &opts.shadow_offset_y);
+  lcfg_lookup_int(&cfg, "shadow-offset-y", &opts.shadow_offset_y);
   // -i (inactive_opacity)
   if (config_lookup_float(&cfg, "inactive-opacity", &dval))
     opts.inactive_opacity = normalize_d(dval) * OPAQUE;

compton.h

@@ -20,12 +20,12 @@
 
 // Whether to enable PCRE regular expression support in blacklists, enabled
 // by default
-#define CONFIG_REGEX_PCRE 1
+// #define CONFIG_REGEX_PCRE 1
 // Whether to enable JIT support of libpcre. This may cause problems on PaX
 // kernels.
-#define CONFIG_REGEX_PCRE_JIT 1
+// #define CONFIG_REGEX_PCRE_JIT 1
 // Whether to enable parsing of configuration files using libconfig
-#define CONFIG_LIBCONFIG 1
+// #define CONFIG_LIBCONFIG 1
 
 // === Includes ===
 
@@ -49,6 +49,12 @@
 
 #ifdef CONFIG_REGEX_PCRE
 #include <pcre.h>
+
+// For compatiblity with <libpcre-8.20
+#ifndef PCRE_STUDY_JIT_COMPILE
+#define PCRE_STUDY_JIT_COMPILE 0
+#endif
+
 #endif
 
 #ifdef CONFIG_LIBCONFIG
@@ -923,7 +929,7 @@ static void
 fork_after(void);
 
 #ifdef CONFIG_LIBCONFIG
-static void
+static inline void
 lcfg_lookup_bool(const config_t *config, const char *path, Bool *value) {
   int ival;
 
@@ -931,6 +937,21 @@ lcfg_lookup_bool(const config_t *config, const char *path, Bool *value) {
     *value = ival;
 }
 
+static inline int
+lcfg_lookup_int(const config_t *config, const char *path, int *value) {
+#ifndef CONFIG_LIBCONFIG_LEGACY
+  return config_lookup_int(config, path, value);
+#else
+  long lval;
+  int ret;
+
+  if ((ret = config_lookup_int(config, path, &lval)))
+    *value = lval;
+
+  return ret;
+#endif
+}
+
 static FILE *
 open_config_file(char *cpath, char **path);