gcc: fail early when --gcc-sanitize-* is combined with -t valgrind

These tools cannot work together (unless we build/check multiple times).
Let the user know immediately, rather than failing with a confusing
error message:

[...]
>>> 2021-05-14 14:36:19	"/usr/bin/mock-unbuffered" "-r" "rhel-9-beta-x86_64" "--plugin-option=tmpfs:keep_mounted=True" "--config-opts=print_main_output=True" "--quiet" "--remove" "valgrind"
No matches found for the following disable plugin patterns: local, spacewalk
Dependencies resolved.
================================================================================
 Package        Architecture Version               Repository              Size
================================================================================
Removing:
 valgrind       x86_64       1:3.17.0-1.el9        @rhel-9.0.0-beta        29 M

Transaction Summary
================================================================================
Remove  1 Package

Freed space: 29 M
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction

Removed:
  valgrind-1:3.17.0-1.el9.x86_64

Complete!

>>> 2021-05-14 14:36:21	"'/usr/bin/mock-unbuffered' '-r' 'rhel-9-beta-x86_64' '--plugin-option=tmpfs:keep_mounted=True' '--config-opts=print_main_output=True' '--quiet' '--shell' 'rpm -qa' | sort -V > /tmp/csmockF6PqOx/sssd-2.4.2-4.el9_0_0/debug/rpm-list-mock.txt"

>>> 2021-05-14 14:36:23	"'/usr/bin/mock-unbuffered' '-r' 'rhel-9-beta-x86_64' '--plugin-option=tmpfs:keep_mounted=True' '--config-opts=print_main_output=True' '--quiet' '--shell' 'rpm -qa --provides' | sort -V > /tmp/csmockF6PqOx/rpm-list-mock-provides.txt"

>>> 2021-05-14 14:36:25	"tar -cP '/usr/share/csmock/scripts' '/usr/bin/csexec' '/usr/bin/csexec-loader' '/usr/lib64/libcsexec-preload.so' '/usr/bin/cswrap' '/usr/lib64/cswrap' '/opt/cov-sa-2021.03' '/tmp/csmockF6PqOx/sssd-2.4.2-4.el9_0_0.src.rpm' | '/usr/bin/mock-unbuffered' '-r' 'rhel-9-beta-x86_64' '--plugin-option=tmpfs:keep_mounted=True' '--config-opts=print_main_output=True' '--quiet' '--shell' 'tar -xC/'"
tar: Removing leading `/' from member names

!!! 2021-05-14 14:36:34	error: tool "valgrind" does not seem to be installed in build root

!!! 2021-05-14 14:36:34	error: post-depinst hook failed

>>> 2021-05-14 14:36:34	"/usr/bin/mock-unbuffered" "-r" "rhel-9-beta-x86_64" "--plugin-option=tmpfs:keep_mounted=True" "--config-opts=print_main_output=True" "--quiet" "--clean"

scan.ini: time-finished = 2021-05-14 14:36:56
scan.ini: exit-code = 1
<<< 2021-05-14 14:36:56	csmock exit code: 1

Author: kdudka

py/plugins/gcc.py

@@ -34,6 +34,7 @@ def __init__(self):
 class Plugin:
     def __init__(self):
         self.enabled = False
+        self.sanitize = False
         self.flags = flags_by_warning_level(0)
         self.csgcca_path = None
 
@@ -45,6 +46,7 @@ def enable(self):
 
     def enable_sanitize(self, props, pkgs, flags):
         self.enabled = True
+        self.sanitize = True
         props.run_check = True
         props.install_pkgs += pkgs
         self.flags.append_flags(flags)
@@ -147,6 +149,9 @@ def handle_args(self, parser, args, props):
                 ["csgrep --mode=json --invert-match --checker COMPILER_WARNING"]
             return
 
+        if self.sanitize and "valgrind" in props.install_pkgs:
+            parser.error("GCC sanitizers are not compatible with valgrind")
+
         props.enable_cswrap()
         props.cswrap_filters += \
             ["csgrep --mode=json --invert-match --checker COMPILER_WARNING --event error"]