--- bip-0.9.3/Makefile.in	2022-03-10 15:57:19.000000000 +0100
+++ bip-0.9.3.new/Makefile.in	2022-05-20 16:47:45.035542388 +0200
@@ -243,8 +243,8 @@
 AWK = @AWK@
 CC = @CC@
 CCDEPMODE = @CCDEPMODE@
-CFLAGS = @CFLAGS@
-CHECK_CFLAGS = @CHECK_CFLAGS@
+CFLAGS ?= @CFLAGS@
+CHECK_CFLAGS ?= @CHECK_CFLAGS@
 CHECK_LIBS = @CHECK_LIBS@
 CPPFLAGS = @CPPFLAGS@
 CSCOPE = @CSCOPE@
@@ -273,7 +273,7 @@
 MAKEINFO = @MAKEINFO@
 MKDIR_P = @MKDIR_P@
 OBJEXT = @OBJEXT@
-OPENSSL_CFLAGS = @OPENSSL_CFLAGS@
+OPENSSL_CFLAGS ?= @OPENSSL_CFLAGS@
 OPENSSL_LIBS = @OPENSSL_LIBS@
 PACKAGE = @PACKAGE@
 PACKAGE_BUGREPORT = @PACKAGE_BUGREPORT@
--- bip-0.9.3/src/Makefile.in	2022-03-10 15:57:19.000000000 +0100
+++ bip-0.9.3.new/src/Makefile.in	2022-05-20 16:50:26.485781660 +0200
@@ -353,7 +353,7 @@
 bipmkpw_LDADD = libbip.a libbiplex.a $(OPENSSL_LIBS)
 AM_YFLAGS = -d
 BUILT_SOURCES = conf.c conf.h lex.c
-AM_CFLAGS = -Wall -Wextra -Werror \
+AM_CFLAGS = -Wall -Wextra  \
 	-O2 \
 	-D_FORTIFY_SOURCE=2 \
 	-fstack-protector-strong -fstack-clash-protection \