It seems, that did did the trick with the esp6.c. However now I'm getting this:
gcc -o build_dir/nsinstall.o -c -std=c99 -g -g -O2 -I/home/dj/GITHUB/openwrt/staging_dir/host/include -I/home/dj/GITHUB/openwrt/staging_dir/hostpkg/include -I/home/dj/GITHUB/openwrt/staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/host/include -Wall -Wshadow -DNSS_NO_GCC48 -DXP_UNIX -DXP_UNIX -DDEBUG -UNDEBUG -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_POSIX_SOURCE -DSQL_MEASURE_USE_TEMP_DIR -D_REENTRANT -DDEBUG -UNDEBUG -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_POSIX_SOURCE -DSQL_MEASURE_USE_TEMP_DIR -D_REENTRANT -DNSS_DISABLE_AVX2 -DNSS_NO_INIT_SUPPORT -DUSE_UTIL_DIRECTLY -DNO_NSPR_10_SUPPORT -DSSL_DISABLE_DEPRECATED_CIPHER_SUITE_NAMES -I../../../dist/build_dir/include -I../../../dist/public/coreconf -I../../../dist/private/coreconf nsinstall.c
nsinstall.c: In function 'main':
nsinstall.c:201:5: warning: implicit declaration of function 'getopt' [-Wimplicit-function-declaration]
while ((opt = getopt(argc, argv, "C:DdlL:Rm:o:g:t")) != EOF) {
^
nsinstall.c:203:20: error: 'optarg' undeclared (first use in this function)
case 'C': cwd = optarg; break;
^
nsinstall.c:203:20: note: each undeclared identifier is reported only once for each function it appears in
nsinstall.c:225:13: error: 'optind' undeclared (first use in this function)
argc -= optind;
^
make[4]: *** [build_dir/nsinstall.o] Error 1
make[4]: Leaving directory `/home/dj/GITHUB/openwrt/build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/nss-3.55/nss/coreconf/nsinstall'
make[3]: *** [/home/dj/GITHUB/openwrt/build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/nss-3.55/.prepared_2991e914492e5b4eb538f2028ed631e4_6664517399ebbbc92a37c5bb081b5c53] Error 2
make[3]: Leaving directory `/home/dj/GITHUB/openwrt/feeds/packages/libs/nss'
time: package/feeds/packages/nss/compile#1.46#0.55#1.78
make[2]: *** [package/feeds/packages/nss/compile] Error 2
make[2]: Leaving directory `/home/dj/GITHUB/openwrt'
make[1]: *** [/home/dj/GITHUB/openwrt/staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/stamp/.package_compile] Error 2
make[1]: Leaving directory `/home/dj/GITHUB/openwrt'
make: *** [world] Error 2
Any idea?
In the mean time, I'll try to go back to the vanilla build, just to get the ipsec / vti related stuff out of the way