Fix #875 - ES version should be strictly validated

When initializing the context in GLContextImpl.setGLFuncAvailability
ES devices must be validated by strictly matching the major version,
otherwise on ES3 devices we were mixing ES1 implementation with ES3
contexts, ultimately crashing in a safeguard.

Signed-off-by: Brice Figureau <brice@daysofwonder.com>

src/jogl/classes/jogamp/opengl/GLContextImpl.java

@@ -1386,6 +1386,8 @@ protected final boolean setGLFunctionAvailability(boolean force, int major, int
         }
     }
 
+    boolean isES = ( CTX_PROFILE_ES & ctxProfileBits ) != 0;
+
     //
     // Validate GL version either by GL-Integer or GL-String
     //
@@ -1424,10 +1426,13 @@ protected final boolean setGLFunctionAvailability(boolean force, int major, int
                 }
                 return false;
             }
-            // Use returned GL version!
-            major = glIntMajor[0];
-            minor = glIntMinor[0];
-            versionValidated = true;
+            // impose strict matching for ES
+            if ((isES && major == glIntMajor[0]) || !isES) {
+                // Use returned GL version!
+                major = glIntMajor[0];
+                minor = glIntMinor[0];
+                versionValidated = true;
+            }
         } else {
             versionGL3IntFailed = true;
         }
@@ -1455,10 +1460,13 @@ protected final boolean setGLFunctionAvailability(boolean force, int major, int
                 }
                 return false;
             }
-            // Use returned GL version!
-            major = hasGLVersionNumber.getMajor();
-            minor = hasGLVersionNumber.getMinor();
-            versionValidated = true;
+            // impose strict matching for ES
+            if ((isES && major == hasGLVersionNumber.getMajor()) || !isES) {
+                // Use returned GL version!
+                major = hasGLVersionNumber.getMajor();
+                minor = hasGLVersionNumber.getMinor();
+                versionValidated = true;
+            }
         }
     }
     if( strictMatch && !versionValidated ) {
@@ -1551,7 +1559,7 @@ protected final boolean setGLFunctionAvailability(boolean force, int major, int
         }
     }
 
-    if( 0 != ( CTX_PROFILE_ES & ctxProfileBits ) ) {
+    if( isES ) {
         if( major >= 3 ) {
             ctxProfileBits |= CTX_IMPL_ES3_COMPAT | CTX_IMPL_ES2_COMPAT ;
             ctxProfileBits |= CTX_IMPL_FBO;