CONFIG: remove libz dependency for scotch (issue #55)

- reduces ThirdParty inter-dependency.
  Only useful for reading in graph files, which are not used
  internally by OpenFOAM.

- Was already removed for Mingw compilation.

etc/makeFiles/scotch/Makefile.inc.OpenFOAM-Darwin.shlib

@@ -29,7 +29,7 @@ CCS        ?= $(CC)
 CCP        ?= mpicc
 CCD         = $(CCP)
 CFLAGS      = $(WM_CFLAGS) -fPIC -O3 \
-    -DCOMMON_FILE_COMPRESS_GZ \
+    -UCOMMON_FILE_COMPRESS \
     -DCOMMON_RANDOM_FIXED_SEED \
     -DSCOTCH_DETERMINISTIC \
     -DSCOTCH_RENAME \
@@ -41,7 +41,7 @@ CFLAGS     += -DINTSIZE64
 endif
 
 CLIBFLAGS   =
-LDFLAGS     = $(WM_LDFLAGS) -lz -lm
+LDFLAGS     = $(WM_LDFLAGS) -lm
 
 MAKE        = make
 CP          = cp

etc/makeFiles/scotch/Makefile.inc.OpenFOAM-Linux.shlib

@@ -29,7 +29,7 @@ CCS        ?= $(CC)
 CCP        ?= mpicc
 CCD         = $(CCP)
 CFLAGS      = $(WM_CFLAGS) -fPIC -O3 \
-    -DCOMMON_FILE_COMPRESS_GZ \
+    -UCOMMON_FILE_COMPRESS \
     -DCOMMON_RANDOM_FIXED_SEED \
     -DSCOTCH_DETERMINISTIC \
     -DSCOTCH_RENAME \
@@ -41,7 +41,7 @@ CFLAGS     += -DINTSIZE64
 endif
 
 CLIBFLAGS   = -shared
-LDFLAGS     = -Xlinker --no-as-needed $(WM_LDFLAGS) -lz -lm -lrt
+LDFLAGS     = -Xlinker --no-as-needed $(WM_LDFLAGS) -lm -lrt
 
 MAKE        = make
 CP          = cp