Clean up build flags

- Clean up build flags for Libreswan. In Libreswan 4.1, these flags are
  now set automatically based on Ubuntu/Debian versions, and no longer
  needed for CentOS/RHEL 7 and 8.
- Ref: https://github.com/libreswan/libreswan/blob/main/mk/defaults/linux.mk
       libreswan/libreswan@c01ffcc1

Author: hwdsl2

extras/vpnupgrade.sh

@@ -169,13 +169,19 @@ fi
 cat > Makefile.inc.local <<'EOF'
 WERROR_CFLAGS=-w
 USE_DNSSEC=false
+EOF
+if [ "$SWAN_VER" != "4.1" ]; then
+cat >> Makefile.inc.local <<'EOF'
 USE_DH31=false
 USE_NSS_AVA_COPY=true
 USE_NSS_IPSEC_PROFILE=false
 USE_GLIBC_KERN_FLIP_HEADERS=true
 EOF
+fi
 if [ "$SWAN_VER" = "3.31" ] || [ "$SWAN_VER" = "3.32" ] || [ "$SWAN_VER" = "4.1" ]; then
   echo "USE_DH2=true" >> Makefile.inc.local
+fi
+if [ "$SWAN_VER" = "3.31" ] || [ "$SWAN_VER" = "3.32" ]; then
   if ! grep -qs IFLA_XFRM_LINK /usr/include/linux/if_link.h; then
     echo "USE_XFRM_INTERFACE_IFLA_HEADER=true" >> Makefile.inc.local
   fi

extras/vpnupgrade_centos.sh

@@ -177,11 +177,15 @@ fi
 cat > Makefile.inc.local <<'EOF'
 WERROR_CFLAGS=-w
 USE_DNSSEC=false
+EOF
+if [ "$SWAN_VER" != "4.1" ]; then
+cat >> Makefile.inc.local <<'EOF'
 USE_DH31=false
 USE_NSS_AVA_COPY=true
 USE_NSS_IPSEC_PROFILE=false
 USE_GLIBC_KERN_FLIP_HEADERS=true
 EOF
+fi
 if [ "$SWAN_VER" = "3.31" ] || [ "$SWAN_VER" = "3.32" ] || [ "$SWAN_VER" = "4.1" ]; then
   echo "USE_DH2=true" >> Makefile.inc.local
   if ! grep -qs IFLA_XFRM_LINK /usr/include/linux/if_link.h; then

vpnsetup.sh

@@ -197,16 +197,9 @@ cat > Makefile.inc.local <<'EOF'
 WERROR_CFLAGS=-w
 USE_DNSSEC=false
 USE_DH2=true
-USE_DH31=false
-USE_NSS_AVA_COPY=true
-USE_NSS_IPSEC_PROFILE=false
-USE_GLIBC_KERN_FLIP_HEADERS=true
 USE_NSS_KDF=false
 FINALNSSDIR=/etc/ipsec.d
 EOF
-if ! grep -qs IFLA_XFRM_LINK /usr/include/linux/if_link.h; then
-  echo "USE_XFRM_INTERFACE_IFLA_HEADER=true" >> Makefile.inc.local
-fi
 if [ "$(packaging/utils/lswan_detect.sh init)" = "systemd" ]; then
   apt-get -yq install libsystemd-dev || exiterr2
 fi

vpnsetup_centos.sh

@@ -194,10 +194,6 @@ cat > Makefile.inc.local <<'EOF'
 WERROR_CFLAGS=-w
 USE_DNSSEC=false
 USE_DH2=true
-USE_DH31=false
-USE_NSS_AVA_COPY=true
-USE_NSS_IPSEC_PROFILE=false
-USE_GLIBC_KERN_FLIP_HEADERS=true
 USE_NSS_KDF=false
 FINALNSSDIR=/etc/ipsec.d
 EOF