diff -uNr a/Makefile.Linux b/Makefile.Linux
--- a/Makefile.Linux	2020-10-22 11:38:44.000000000 +0300
+++ b/Makefile.Linux	2020-10-22 22:38:26.257745810 +0300
@@ -8,13 +8,13 @@
 # library support. Add -DSAFESQL for poorely written ODBC library / drivers.
 
 BUILDDIR = ../bin/
-CC = gcc
+CC ?= gcc
 
-CFLAGS = -g  -fPIC -O2 -fno-strict-aliasing -c -pthread -DWITHSPLICE -D_GNU_SOURCE -DGETHOSTBYNAME_R -D_THREAD_SAFE -D_REENTRANT -DNOODBC -DWITH_STD_MALLOC -DFD_SETSIZE=4096 -DWITH_POLL -DWITH_NETFILTER
+CFLAGS += -fPIC -fno-strict-aliasing -c -pthread -DWITHSPLICE -D_GNU_SOURCE -DGETHOSTBYNAME_R -D_THREAD_SAFE -D_REENTRANT -DNOODBC -DWITH_STD_MALLOC -DFD_SETSIZE=4096 -DWITH_POLL -DWITH_NETFILTER
 COUT = -o 
-LN = gcc
+LN ?= gcc
 DCFLAGS = 
-LDFLAGS = -fPIE -O2 -fno-strict-aliasing -pthread
+LDFLAGS += -fPIE -fno-strict-aliasing -pthread
 DLFLAGS = -shared
 DLSUFFICS = .ld.so
 # -lpthreads may be reuqired on some platforms instead of -pthreads
@@ -39,12 +39,12 @@
 include Makefile.inc
 
 allplugins:
-	@list='$(PLUGINS)'; for p in $$list; do cp Makefile Makefile.var plugins/$$p; cd plugins/$$p ; make ;	cd ../.. ; done
+	@list='$(PLUGINS)'; for p in $$list; do cp Makefile Makefile.var plugins/$$p; cd plugins/$$p ; $(MAKE) ; cd ../.. ; done
 
 DESTDIR		=
 prefix		= 
 exec_prefix	= $(prefix)
-man_prefix	= /usr/share
+man_prefix	= $(prefix)/usr/share
 
 INSTALL		= /usr/bin/install
 INSTALL_BIN	= $(INSTALL) -m 755