foamyMesh: Simplify support for system CGAL installation

applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/Make/options

@@ -23,8 +23,7 @@ EXE_INC = \
     -I$(LIB_SRC)/triSurface/lnInclude \
     -I$(LIB_SRC)/sampling/lnInclude \
     -I$(LIB_SRC)/mesh/snappyHexMesh/lnInclude \
-    -IPrintTable \
-    -I/usr/include
+    -IPrintTable
 
 LIB_LIBS = \
     ${CGAL_LIBS} \

applications/utilities/mesh/generation/foamyMesh/foamyQuadMesh/Make/options

@@ -21,8 +21,7 @@ EXE_INC = \
     -I$(LIB_SRC)/sampling/lnInclude \
     -I$(LIB_SRC)/triSurface/lnInclude \
     -I$(LIB_SRC)/fileFormats/lnInclude \
-    -I$(LIB_SRC)/mesh/snappyHexMesh/lnInclude \
-    -I/usr/include
+    -I$(LIB_SRC)/mesh/snappyHexMesh/lnInclude
 
 EXE_LIBS = \
     $(CGAL_LIBS) \

wmake/rules/General/CGAL

@@ -2,7 +2,8 @@ CGAL_INC = \
     -I$(CGAL_ARCH_PATH)/include \
     -I$(MPFR_ARCH_PATH)/include \
     -I$(GMP_ARCH_PATH)/include \
-    -I$(BOOST_ARCH_PATH)/include
+    -I$(BOOST_ARCH_PATH)/include \
+    -I/usr/include
 
 CGAL_LIBS = \
     -L$(MPFR_ARCH_PATH)/lib$(WM_COMPILER_LIB_ARCH) \