diff --git a/compton.c b/compton.c
index 65d9fa752..f249b1881 100644
--- a/compton.c
+++ b/compton.c
@@ -2587,6 +2587,7 @@ win_update_opacity_rule(session_t *ps, win *w) {
   if (IsViewable != w->a.map_state)
     return;
 
+#ifdef CONFIG_C2
   // If long is 32-bit, unfortunately there's no way could we express "unset",
   // so we just entirely don't distinguish "unset" and OPAQUE
   opacity_t opacity = OPAQUE;
@@ -2602,6 +2603,7 @@ win_update_opacity_rule(session_t *ps, win *w) {
   else if (OPAQUE != w->opacity_set)
     wid_rm_opacity_prop(ps, w->id);
   w->opacity_set = opacity;
+#endif
 }
 
 /**
@@ -5162,6 +5164,7 @@ parse_geometry_end:
  */
 static inline bool
 parse_rule_opacity(session_t *ps, const char *src) {
+#ifdef CONFIG_C2
   // Find opacity value
   char *endptr = NULL;
   long val = strtol(src, &endptr, 0);
@@ -5186,6 +5189,10 @@ parse_rule_opacity(session_t *ps, const char *src) {
   // Parse pattern
   // I hope 1-100 is acceptable for (void *)
   return c2_parsed(ps, &ps->o.opacity_rules, endptr, (void *) val);
+#else
+  printf_errf("(\"%s\"): Condition support not compiled in.", src);
+  return false;
+#endif
 }
 
 #ifdef CONFIG_LIBCONFIG
diff --git a/opengl.c b/opengl.c
index 965356593..800ebd585 100644
--- a/opengl.c
+++ b/opengl.c
@@ -104,12 +104,14 @@ glx_init(session_t *ps, bool need_render) {
     ps->psglx = cmalloc(1, glx_session_t);
     memcpy(ps->psglx, &CGLX_SESSION_DEF, sizeof(glx_session_t));
 
+#ifdef CONFIG_VSYNC_OPENGL_GLSL
     for (int i = 0; i < MAX_BLUR_PASS; ++i) {
       glx_blur_pass_t *ppass = &ps->psglx->blur_passes[i];
       ppass->unifm_factor_center = -1;
       ppass->unifm_offset_x = -1;
       ppass->unifm_offset_y = -1;
     }
+#endif
   }
 
   glx_session_t *psglx = ps->psglx;