mesa: Apply MSVC portability fixes from Alan Hourihane.
diff --git a/src/mesa/shader/prog_execute.c b/src/mesa/shader/prog_execute.c
index e9957d3..32b6ff4 100644
--- a/src/mesa/shader/prog_execute.c
+++ b/src/mesa/shader/prog_execute.c
@@ -93,7 +93,7 @@
                 source->File == PROGRAM_STATE_VAR ||
                 source->File == PROGRAM_UNIFORM);
          params = machine->CurProgram->Parameters;
-         if (reg < 0 || reg >= params->NumParameters)
+         if (reg < 0 || reg >= (GLint)params->NumParameters)
             return ZeroVec;
          else
             return params->ParameterValues[reg];
@@ -228,7 +228,7 @@
                     const struct gl_program_machine *machine,
                     char xOrY, GLfloat result[4])
 {
-   if (source->File == PROGRAM_INPUT && source->Index < machine->NumDeriv) {
+   if (source->File == PROGRAM_INPUT && source->Index < (GLint)machine->NumDeriv) {
       const GLint col = machine->CurElement;
       const GLfloat w = machine->Attribs[FRAG_ATTRIB_WPOS][col][3];
       const GLfloat invQ = 1.0f / w;
@@ -507,7 +507,7 @@
 {
    const GLuint numInst = program->NumInstructions;
    const GLuint maxExec = 10000;
-   GLint pc, numExec = 0;
+   GLuint pc, numExec = 0;
 
    machine->CurProgram = program;