diff --git a/src/kits/opengl/Jamfile b/src/kits/opengl/Jamfile
index 4ac0e495dd..4391a643e7 100644
--- a/src/kits/opengl/Jamfile
+++ b/src/kits/opengl/Jamfile
@@ -6,7 +6,7 @@ UsePrivateHeaders opengl ;
 
 if $(TARGET_PLATFORM) != haiku {
 	UseHeaders [ FDirName $(HAIKU_TOP) headers os opengl ] : true ;
-		# We need the public GL headers also when not compiling for Haiku.
+		# We need our public GL headers also when not compiling for Haiku.
 }
 
 
@@ -19,20 +19,30 @@ UseHeaders [ FDirName $(SUBDIR) mesa shader ] ;
 UseHeaders [ FDirName $(SUBDIR) mesa swrast ] ;
 UseHeaders [ FDirName $(SUBDIR) mesa swrast_setup ] ;
 
-SubDirCcFlags 
-	-DBEOS_THREADS 
-	-DGNU_ASSEMBLER 
-	-DUSE_X86_ASM 
-	-DUSE_MMX_ASM 
-	-DUSE_3DNOW_ASM 
-	-DUSE_SSE_ASM ;
-SubDirC++Flags 
-	-DBEOS_THREADS 
-	-DGNU_ASSEMBLER 
-	-DUSE_X86_ASM 
-	-DUSE_MMX_ASM 
-	-DUSE_3DNOW_ASM 
-	-DUSE_SSE_ASM ;
+{
+       local defines ;
+       defines = BEOS_THREADS GNU_ASSEMBLER ;
+
+	if $(TARGET_ARCH) = x86 {
+		defines += USE_X86_ASM USE_MMX_ASM USE_3DNOW_ASM USE_SSE_ASM ;
+	} else if $(TARGET_ARCH) = ppc {
+		# Not yet supported, as current Mesa3D PPC assembly is Linux-dependent!
+		# defines += USE_PPC_ASM ;
+	}
+
+	defines = [ FDefines $(defines) ] ;
+        SubDirCcFlags $(defines) ;
+        SubDirC++Flags $(defines) ;
+}
+
+local arch_sources ;
+if $(TARGET_ARCH) = x86 {
+	# On x86 platform, use the faster GL API dispatching assembly code!
+	arch_sources = glapi_x86.S ;
+} else {
+	# For non-X86 platforms, no assembly code yet.
+	arch_sources = ;
+}
 
 SEARCH_SOURCE += [ FDirName $(SUBDIR) mesa $(TARGET_ARCH) ] ;
 
@@ -41,8 +51,8 @@ SharedLibrary libGL.so :
 	GLDispatcher.cpp
 	GLRenderer.cpp
 
-	# mesa/$(TARGET_ARCH)
-	glapi_$(TARGET_ARCH).S
+	# Mesa optimized GL dispatching code (if any) for this target architecture 
+	$(arch_sources)
 	: 
 	# GLU API is included in libGL.so under BeOS R5, not a separate libglu.so library
 	<opengl>sgi-glu.o
diff --git a/src/kits/opengl/glu/Jamfile b/src/kits/opengl/glu/Jamfile
index aff2551ca2..c75a0c1ac2 100644
--- a/src/kits/opengl/glu/Jamfile
+++ b/src/kits/opengl/glu/Jamfile
@@ -4,7 +4,7 @@ SetSubDirSupportedPlatformsBeOSCompatible ;
 
 if $(TARGET_PLATFORM) != haiku {
 	UseHeaders [ FDirName $(HAIKU_TOP) headers os opengl ] : true ;
-		# We need the public GL headers also when not compiling for Haiku.
+		# We need our public GL headers also when not compiling for Haiku.
 }
 
 UseHeaders [ FDirName $(SUBDIR) include ] ;
diff --git a/src/kits/opengl/glut/Jamfile b/src/kits/opengl/glut/Jamfile
index 7eeb038d14..6024ef45a8 100644
--- a/src/kits/opengl/glut/Jamfile
+++ b/src/kits/opengl/glut/Jamfile
@@ -4,7 +4,7 @@ SetSubDirSupportedPlatformsBeOSCompatible ;
 
 if $(TARGET_PLATFORM) != haiku {
 	UseHeaders [ FDirName $(HAIKU_TOP) headers os opengl ] : true ;
-		# We need the public GL headers also when not compiling for Haiku.
+		# We need our public GL headers also when not compiling for Haiku.
 }
 
 MergeObject <opengl>glut.o :
diff --git a/src/kits/opengl/mesa/Jamfile b/src/kits/opengl/mesa/Jamfile
index 626d59fcf5..4b0b131c70 100644
--- a/src/kits/opengl/mesa/Jamfile
+++ b/src/kits/opengl/mesa/Jamfile
@@ -4,7 +4,7 @@ SetSubDirSupportedPlatformsBeOSCompatible ;
 
 if $(TARGET_PLATFORM) != haiku {
 	UseHeaders [ FDirName $(HAIKU_TOP) headers os opengl ] : true ;
-		# We need the public GL headers also when not compiling for Haiku.
+		# We need our not platform one, public GL headers also when not compiling for Haiku.
 }
 
 UsePrivateHeaders opengl ;
@@ -26,50 +26,73 @@ SEARCH_SOURCE += [ FDirName $(SUBDIR) swrast ] ;
 SEARCH_SOURCE += [ FDirName $(SUBDIR) swrast_setup ] ;
 SEARCH_SOURCE += [ FDirName $(SUBDIR) tnl ] ;
 
-SEARCH_SOURCE += [ FDirName $(SUBDIR) x86 ] ;
-SEARCH_SOURCE += [ FDirName $(SUBDIR) sparc ] ;
-SEARCH_SOURCE += [ FDirName $(SUBDIR) ppc ] ;
+{
+       local defines ;
+	defines = BEOS_THREADS GNU_ASSEMBLER ;
 
+	if $(TARGET_ARCH) = x86 {
+		defines += USE_X86_ASM USE_MMX_ASM USE_3DNOW_ASM USE_SSE_ASM ;
+	} else {
+		# Not yet supported, as current Mesa3D PPC assembly is Linux-dependent!
+                # defines += USE_PPC_ASM ;
+	}
 
-SubDirCcFlags 
-	-DBEOS_THREADS 
-	-DGNU_ASSEMBLER 
-	-DUSE_X86_ASM 
-	-DUSE_MMX_ASM 
-	-DUSE_3DNOW_ASM 
-	-DUSE_SSE_ASM ;
-
-local archSources ;
+	defines = [ FDefines $(defines) ] ;
+	SubDirCcFlags $(defines) ;
+	SubDirC++Flags $(defines) ;
+}
 
+local arch_sources ;
 if $(TARGET_ARCH) = x86 {
-	archSources =
+
+	arch_sources = 
+		common_x86.c
 		common_x86_asm.S
-		x86_xform2.S	
-		x86_xform3.S	
-		x86_xform4.S	
-		x86_cliptest.S	
-		mmx_blend.S		
-		3dnow_xform1.S	
-		3dnow_xform2.S	
-		3dnow_xform3.S	
-		3dnow_xform4.S	
-		3dnow_normal.S	
-		sse_xform1.S	
-		sse_xform2.S	
-		sse_xform3.S	
-		sse_xform4.S	
+
+		x86.c
+		x86_xform2.S
+		x86_xform3.S
+		x86_xform4.S
+		x86_cliptest.S
+		mmx_blend.S
+		3dnow.c
+		3dnow_xform1.S
+		3dnow_xform2.S
+		3dnow_xform3.S
+		3dnow_xform4.S
+		3dnow_normal.S
+		sse.c
+		sse_xform1.S
+		sse_xform2.S
+		sse_xform3.S
+		sse_xform4.S
 		sse_normal.S
 		read_rgba_span_x86.S
 
-		# tnl
 		t_vtx_x86_gcc.S
-	;
-} else {
-	archSources =
+		;
+
+} else if $(TARGET_ARCH) = ppc {
+
+	arch_sources = 
+		common_ppc.c
 		t_vtx_generic.c
-	;
+		;
+
+} else if $(TARGET_ARCH) = sparc {
+
+	arch_sources = 
+		sparc.c 
+		t_vtx_generic.c 
+		;
+
+} else {
+	arch_sources = t_vtx_generic.c ;
 }
 
+SEARCH_SOURCE += [ FDirName $(SUBDIR) $(TARGET_ARCH) ] ;
+
+
 StaticLibrary libmesa.a : 
 
 	# main
@@ -217,20 +240,8 @@ StaticLibrary libmesa.a :
 	program.c
 	shaderobjects.c
 
-	# x86
-	common_x86.c
-	x86.c
-	3dnow.c
-	sse.c
+	$(arch_sources)
 
-	# sparc
-	sparc.c
-
-	# ppc	
-	common_ppc.c
-
-	$(archSources)
-	
 	# glapi
 	glapi.c
 	glthread.c