Parlib and other user libs are built with -fPIC

Also, this collects the common user library flags into the top-level
Makefile.
diff --git a/Makefile b/Makefile
index 106fd5f..0e5044a 100644
--- a/Makefile
+++ b/Makefile
@@ -349,8 +349,9 @@
 
 CFLAGS_USER += -O2 -std=gnu99 -fno-stack-protector -fgnu89-inline
 CXXFLAGS_USER += -O2
+CFLAGS_USER_LIBS += -fPIC -static -fomit-frame-pointer -g
 
-export CFLAGS_USER CXXFLAGS_USER
+export CFLAGS_USER CXXFLAGS_USER CFLAGS_USER_LIBS
 
 # Akaros include stuff (includes custom make targets and user overrides)
 # =========================================================================
diff --git a/user/benchutil/Makefile b/user/benchutil/Makefile
index 9adbe3e..136859b 100644
--- a/user/benchutil/Makefile
+++ b/user/benchutil/Makefile
@@ -1,5 +1,5 @@
 ARCH ?= none	# catch bugs
-CFLAGS_USER += -static -fomit-frame-pointer -g
+CFLAGS_USER += $(CFLAGS_USER_LIBS)
 LIBNAME = benchutil
 # DEPLIBS passed in from the top-level Makefile
 DEPLIBS := $(DEPLIBS)
diff --git a/user/bsd/Makefile b/user/bsd/Makefile
index c82edcd..4330b28 100644
--- a/user/bsd/Makefile
+++ b/user/bsd/Makefile
@@ -1,5 +1,5 @@
 ARCH ?= none	# catch bugs
-CFLAGS_USER += -static -fomit-frame-pointer -g
+CFLAGS_USER += $(CFLAGS_USER_LIBS)
 LIBNAME = bsd
 # DEPLIBS passed in from the top-level Makefile
 DEPLIBS := $(DEPLIBS)
diff --git a/user/iplib/Makefile b/user/iplib/Makefile
index 1cc42e3..30a7b7e 100644
--- a/user/iplib/Makefile
+++ b/user/iplib/Makefile
@@ -1,5 +1,5 @@
 ARCH ?= none	# catch bugs
-CFLAGS_USER += -static -fomit-frame-pointer -g
+CFLAGS_USER += $(CFLAGS_USER_LIBS)
 LIBNAME = iplib
 # DEPLIBS passed in from the top-level Makefile
 DEPLIBS := $(DEPLIBS)
diff --git a/user/ndblib/Makefile b/user/ndblib/Makefile
index 490813d..670eec8 100644
--- a/user/ndblib/Makefile
+++ b/user/ndblib/Makefile
@@ -1,5 +1,5 @@
 ARCH ?= none	# catch bugs
-CFLAGS_USER += -static -fomit-frame-pointer -g
+CFLAGS_USER += $(CFLAGS_USER_LIBS)
 LIBNAME = ndb
 # DEPLIBS passed in from the top-level Makefile
 DEPLIBS := $(DEPLIBS)
diff --git a/user/parlib/Makefile b/user/parlib/Makefile
index 9a553cf..e89b43c 100644
--- a/user/parlib/Makefile
+++ b/user/parlib/Makefile
@@ -1,5 +1,5 @@
 ARCH ?= none	# catch bugs
-CFLAGS_USER += -static -fomit-frame-pointer -g
+CFLAGS_USER += $(CFLAGS_USER_LIBS)
 LIBNAME = parlib
 # DEPLIBS passed in from the top-level Makefile
 DEPLIBS := $(DEPLIBS)
diff --git a/user/pthread/Makefile b/user/pthread/Makefile
index 498685e..a52eb56 100644
--- a/user/pthread/Makefile
+++ b/user/pthread/Makefile
@@ -1,5 +1,5 @@
 ARCH ?= none # catch bugs
-CFLAGS_USER += -static -fomit-frame-pointer -g
+CFLAGS_USER += $(CFLAGS_USER_LIBS)
 LIBNAME = pthread
 # DEPLIBS passed in from the top-level Makefile
 DEPLIBS := $(DEPLIBS)