Fix portability regarding compat/base64, python mod cflags and c compilers like zig cc

[michaelortmann]

Found by: michaelortmann
Patch by: michaelortmann
Fixes:

One-line summary:
Fix portability regarding compat/base64, python mod cflags and c compilers like zig cc

Additional description (if needed):
$ CC="zig cc -Wno-deprecated-non-prototype" ./configure && make config && make works now :)

Test cases demonstrating functionality (if applicable):
Fixes all make errors with zig cc:
1.

zig cc -Wno-deprecated-non-prototype -std=gnu99 -g -O2 -pipe -Wall -I.. -I..  -DHAVE_CONFIG_H -I/usr/include -lpthread -o ../eggdrop bg.o botcmd.o botmsg.o botnet.o chanprog.o cmds.o dcc.o dccutil.o dns.o flags.o language.o match.o main.o mem.o misc.o misc_file.o modules.o net.o rfc1459.o tcl.o tcldcc.o tclhash.o tclmisc.o tcluser.o tls.o userent.o userrec.o users.o  -L/usr/lib -ltcl8.6  -lz -lpthread -lm -lssl -lcrypto  md5/md5c.o compat/*.o `cat mod/mod.xlibs`
ld.lld: error: undefined symbol: b64_ntop
>>> referenced by modules.c:182
>>>               modules.o:(global_table)

ld.lld: error: undefined symbol: b64_pton
>>> referenced by modules.c:182
>>>               modules.o:(global_table)
make[2]: *** [Makefile:48: link] Error 1

Before (note the underscores):

$ nm src/compat/base64.o
0000000000000000 T __b64_ntop
00000000000001c0 T __b64_pton

After:

$ nm src/compat/base64.o
0000000000000000 T egg_b64_ntop
00000000000001c0 T egg_b64_pton

2.

zig cc -Wno-deprecated-non-prototype -fPIC -I/usr/include/python3.13 -I/usr/include/python3.13  -fno-strict-overflow -Wsign-compare -march=x86-64 -mtune=generic -O3 -pipe -fno-plt -fexceptions         -Wp,-D_FORTIFY_SOURCE=3 -Wformat -Werror=format-security         -fstack-clash-protection -fcf-protection         -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -g -ffile-prefix-map=/build/python/src=/usr/src/debug/python -flto=auto -ffat-lto-objects -DNDEBUG -g -O3 -Wall -std=gnu99 -g -O2 -pipe -Wall -I. -I../../.. -I../../.. -I../../../src/mod  -DHAVE_CONFIG_H -I/usr/include  -DMAKING_MODS -c .././python.mod/python.c && mv -f python.o ../
error: unsupported preprocessor arg: -D_FORTIFY_SOURCE
make[2]: *** [Makefile:19: ../python.o] Error 1

3.

zig cc -Wno-deprecated-non-prototype -fPIC -I/usr/include/python3.13 -I/usr/include/python3.13 -fno-strict-overflow -Wsign-compare -march=x86-64 -mtune=generic -O3 -pipe -fno-plt -fexceptions -std=gnu99 -g -O2 -pipe -Wall -I. -I../../.. -I../../.. -I../../../src/mod  -DHAVE_CONFIG_H -I/usr/include  -DMAKING_MODS -c .././python.mod/python.c && mv -f python.o ../
error: unknown target CPU 'generic'
note: valid target CPU values are: nocona, core2, penryn, bonnell, atom, silvermont, slm, goldmont, goldmont-plus, tremont, nehalem, corei7, westmere, sandybridge, corei7-avx, ivybridge, core-avx-i, haswell, core-avx2, broadwell, skylake, skylake-avx512, skx, cascadelake, cooperlake, cannonlake, icelake-client, rocketlake, icelake-server, tigerlake, sapphirerapids, alderlake, raptorlake, meteorlake, arrowlake, arrowlake-s, lunarlake, gracemont, pantherlake, sierraforest, grandridge, graniterapids, graniterapids-d, emeraldrapids, clearwaterforest, knl, knm, k8, athlon64, athlon-fx, opteron, k8-sse3, athlon64-sse3, opteron-sse3, amdfam10, barcelona, btver1, btver2, bdver1, bdver2, bdver3, bdver4, znver1, znver2, znver3, znver4, znver5, x86-64, x86-64-v2, x86-64-v3, x86-64-v4
make[2]: *** [Makefile:19: ../python.o] Error 1

[michaelortmann]

Something is still not right regarding base64: Can't load modules server: /home/michael/eggdrop/modules/server.so: undefined symbol: __b64_pton

[michaelortmann]

this was symbol resolving hell. finally i fixed it by putting the include for resolv.h in one and only one place in eggdrop and fix it proper there. if configure didnt find a way to use a system base64 it will make eggdrop use its own compat functions. still eggdrop would include resolv.h for dns and stuff, and resolv.h was still defining b64() funcs to __b64() funcs in some cases / systems. the the final fix was to undef b64() funcs right after including resolv.h if HAVE_BASE64 wasnt set by configure.