build: OS X compilation fixes: use GL_INVALID_ENUM instead of GL_INVALID_INDEX

and support automake 1.12 in the bootstrap script.

bootstrap

@@ -46,7 +46,7 @@ aclocalflags="`sed -ne 's/^[ \t]*ACLOCAL_AMFLAGS[ \t]*=//p' Makefile.am 2>/dev/n
 
 # Check for automake
 amvers="no"
-for v in 11 10 9 8 7 6 5; do
+for v in 12 11 10 9 8 7 6 5; do
   if automake-1.${v} --version >/dev/null 2>&1; then
     amvers="-1.${v}"
     break

src/gpu/framebuffer.cpp

@@ -82,8 +82,8 @@ FrameBuffer::FrameBuffer(ivec2 size)
 
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                            GL_TEXTURE_2D, m_data->m_texture, 0);
-    m_data->m_depth = GL_INVALID_INDEX;
-    if (depth != GL_INVALID_INDEX)
+    m_data->m_depth = GL_INVALID_ENUM;
+    if (depth != GL_INVALID_ENUM)
     {
         glGenRenderbuffers(1, &m_data->m_depth);
         glBindRenderbuffer(GL_RENDERBUFFER, m_data->m_depth);
@@ -106,7 +106,7 @@ FrameBuffer::~FrameBuffer()
 #elif GL_VERSION_1_1
     glDeleteFramebuffers(1, &m_data->m_fbo);
     glDeleteTextures(1, &m_data->m_texture);
-    if (m_data->m_depth != GL_INVALID_INDEX)
+    if (m_data->m_depth != GL_INVALID_ENUM)
         glDeleteRenderbuffers(1, &m_data->m_depth);
 #else
 #endif