glsl: Add default precision qualifiers for ES builtins

Once the compiler proplerly checks for default precision qualifiers,
these shaders will cease to compile.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Cc: "9.2" <mesa-stable@lists.freedesktop.org>

src/glsl/builtins/profiles/100es.frag

@@ -1,4 +1,6 @@
 #version 100
+precision highp float;
+
 vec4 texture2D       (sampler2D sampler, vec2 coord, float bias);
 vec4 texture2DProj   (sampler2D sampler, vec3 coord, float bias);
 vec4 texture2DProj   (sampler2D sampler, vec4 coord, float bias);

src/glsl/builtins/profiles/300es.frag

@@ -1,4 +1,5 @@
 #version 300 es
+precision highp float;
 
 /* texture - bias variants */
  vec4 texture( sampler2D sampler, vec2 P, float bias);

src/glsl/builtins/profiles/OES_EGL_image_external.glsl

@@ -1,5 +1,6 @@
 #version 100
 #extension GL_OES_EGL_image_external : enable
+precision highp float;
 
 vec4 texture2D(samplerExternalOES sampler, vec2 coord);
 vec4 texture2DProj(samplerExternalOES sampler, vec3 coord);

src/glsl/builtins/profiles/OES_standard_derivatives.frag

@@ -1,5 +1,6 @@
 #version 100
 #extension GL_OES_standard_derivatives : enable
+precision highp float;
 
 /*
  * 8.8 - Fragment Processing Functions

src/glsl/builtins/profiles/OES_texture_3D.frag

@@ -1,5 +1,6 @@
 #version 100
 #extension GL_OES_texture_3D : enable
+precision highp float;
 
 vec4 texture3D (sampler3D sampler, vec3 coord);
 vec4 texture3DProj (sampler3D sampler, vec4 coord);