A set of assorted tweaks and cleanups in the build system.

[codecov-commenter]

Codecov Report

Patch coverage has no change and project coverage change: +0.08 :tada:

Comparison is base (1e90fc8) 70.48% compared to head (5570009) 70.57%.

:exclamation: Current head 5570009 differs from pull request most recent head 887ac36. Consider uploading reports for the commit 887ac36 to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## criu-dev #2211 +/- ## ============================================ + Coverage 70.48% 70.57% +0.08% ============================================ Files 133 133 Lines 33508 33563 +55 ============================================ + Hits 23619 23687 +68 + Misses 9889 9876 -13 ``` | [Impacted Files](https://app.codecov.io/gh/checkpoint-restore/criu/pull/2211?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None) | Coverage Δ | | |---|---|---| | [criu/libnetlink.c](https://app.codecov.io/gh/checkpoint-restore/criu/pull/2211?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-Y3JpdS9saWJuZXRsaW5rLmM=) | `75.26% <ø> (-0.27%)` | :arrow_down: | ... and [8 files with indirect coverage changes](https://app.codecov.io/gh/checkpoint-restore/criu/pull/2211/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None)

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[0x7f454c46]

From: Uros Prestor <urosp@google.com> Should have SoB line that certifies that the author agrees with GPL2 license and all that legal staff. Besides, I see your Gerrit's Change-IDs, which probably should be removed as they don't give anyone any context outside Google (or is your Gerrit publically visible?). That's what we usually ask Virtuozzo/Parallels folks - to remove any BUG links that are not visible/accessible to CRIU contributors.

Other than this, LGTM

[0x7f454c46]

If you wish, you can add this on top: https://github.com/0x7f454c46/criu/commit/0126dbeb21df3e32b094ebc0adbc7cc7e294a278

[avagin]

diff --git a/Makefile.config b/Makefile.config
index 9950134a4..721e5d2be 100644
--- a/Makefile.config
+++ b/Makefile.config
@@ -84,10 +84,9 @@ FEATURES_LIST        := TCP_REPAIR STRLCPY STRLCAT PTRACE_PEEKSIGINFO \
 # $1 - config name
 define gen-feature-test
 ifeq ($$(call try-cc,$$(FEATURE_TEST_$(1)),$$(LIBS_FEATURES),$$(DEFINES)),true)
-       echo '#define CONFIG_HAS_$(1)' >> $$@
-       $(Q) echo '' >> $$@
+       $(Q) echo '#define CONFIG_HAS_$(1)' >> $$@
 else
-       echo '#undef CONFIG_HAS_$(1)' > /dev/null
+       $(Q) echo '// CONFIG_HAS_$(1) is not set' >> $$@
 endif
 endef

avagin@avagin:~/git/checkpoint-restore/criu$ make V=1 include/common/config.h
Note: Building criu without amdgpu_plugin.
Note: libdrm and libdrm_amdgpu are required to build amdgpu_plugin.
Makefile.config:53: Warn: you have no libnftables installed
Makefile.config:54: Warn: Building without nftables support
touch .config
echo '#ifndef __CR_CONFIG_H__'              > include/common/config.h
echo '#define __CR_CONFIG_H__'              >> include/common/config.h
echo ''                         >> include/common/config.h
echo '#define CONFIG_HAS_TCP_REPAIR' >> include/common/config.h
echo '#define CONFIG_HAS_STRLCPY' >> include/common/config.h
echo '#define CONFIG_HAS_STRLCAT' >> include/common/config.h
echo '// CONFIG_HAS_PTRACE_PEEKSIGINFO is not set' >> include/common/config.h
echo '#define CONFIG_HAS_SETPROCTITLE_INIT' >> include/common/config.h
echo '// CONFIG_HAS_MEMFD is not set' >> include/common/config.h
echo '#define CONFIG_HAS_TCP_REPAIR_WINDOW' >> include/common/config.h
echo '#define CONFIG_HAS_MEMFD_CREATE' >> include/common/config.h
echo '#define CONFIG_HAS_OPENAT2' >> include/common/config.h
echo '// CONFIG_HAS_NO_LIBC_RSEQ_DEFS is not set' >> include/common/config.h
cat .config | sed -n -e '/^[^#]/s/^/#define CONFIG_/p' >> include/common/config.h
echo '#endif /* __CR_CONFIG_H__ */'         >> include/common/config.h
avagin@avagin:~/git/checkpoint-restore/criu$ cat include/common/config.h
#ifndef __CR_CONFIG_H__
#define __CR_CONFIG_H__

#define CONFIG_HAS_TCP_REPAIR
#define CONFIG_HAS_STRLCPY
#define CONFIG_HAS_STRLCAT
// CONFIG_HAS_PTRACE_PEEKSIGINFO is not set
#define CONFIG_HAS_SETPROCTITLE_INIT
// CONFIG_HAS_MEMFD is not set
#define CONFIG_HAS_TCP_REPAIR_WINDOW
#define CONFIG_HAS_MEMFD_CREATE
#define CONFIG_HAS_OPENAT2
// CONFIG_HAS_NO_LIBC_RSEQ_DEFS is not set
#endif /* __CR_CONFIG_H__ */