fix shaders on osx

data/shaders/comp-draw.glsl

@@ -24,7 +24,7 @@ uniform sampler2D tex_stroke;
 uniform sampler2D tex_mask;
 uniform mediump float alpha;
 uniform mediump float stroke_alpha;
-uniform mediump int blend_mode;
+uniform int blend_mode;
 uniform mediump vec2 resolution;
 uniform bool lock;
 uniform bool mask;
@@ -32,7 +32,7 @@ uniform bool mask;
 uniform bool use_dual;
 uniform sampler2D tex_dual;
 uniform mediump float dual_alpha;
-uniform mediump int dual_blend_mode;
+uniform int dual_blend_mode;
 
 uniform bool use_pattern;
 uniform sampler2D tex_pattern;
@@ -41,8 +41,8 @@ uniform mediump float pattern_bright;
 uniform mediump float pattern_contr;
 uniform mediump float pattern_depth;
 uniform mediump vec2 pattern_offset;
-uniform mediump bool pattern_invert;
-uniform mediump int patt_blend_mode;
+uniform bool pattern_invert;
+uniform int patt_blend_mode;
 
 in mediump vec2 uv;
 out mediump vec4 frag;

data/shaders/stroke.glsl

@@ -41,8 +41,8 @@ uniform mediump float pattern_bright;
 uniform mediump float pattern_contr;
 uniform mediump float pattern_depth;
 uniform mediump vec2 pattern_offset;
-uniform mediump bool pattern_invert;
-uniform mediump int patt_blend_mode;
+uniform bool pattern_invert;
+uniform int patt_blend_mode;
 
 in mediump vec2 uv;
 in mediump vec2 uv_2;

src/shader.cpp

@@ -147,6 +147,8 @@ bool Shader::reload()
         destroy();
         return load(m_path);
     }
+    
+    return false;
 }
 
 bool Shader::create(const char* vertex, const char* fragment)