cmake: Rework flags summary

[hebasto]

This was requested in hebasto/bitcoin#221. The implementation follows the same approach as in hebasto/bitcoin#93.

Here are a few excerpts from the summaries:

• Linux:

Cross compiling ....................... FALSE
Valgrind .............................. ON
Preprocessor defined macros ........... ENABLE_MODULE_ELLSWIFT=1 ENABLE_MODULE_SCHNORRSIG=1 ENABLE_MODULE_EXTRAKEYS=1 ENABLE_MODULE_ECDH=1 ECMULT_WINDOW_SIZE=15 COMB_BLOCKS=11 COMB_TEETH=6 USE_ASM_X86_64=1 VALGRIND
C compiler ............................ GNU 13.2.0, /usr/bin/cc
CMAKE_BUILD_TYPE ...................... RelWithDebInfo
C compiler flags ...................... -O2 -g -std=c90 -fPIC -fvisibility=hidden -pedantic -Wall -Wcast-align -Wcast-align=strict -Wextra -Wnested-externs -Wno-long-long -Wno-overlength-strings -Wno-unused-function -Wshadow -Wstrict-prototypes -Wundef
Linker flags .......................... -fPIC -O2 -g -Wl,-soname,libsecp256k1.so.2

NOTE: The summary above may not exactly match the final applied build flags
      if any additional CMAKE_* or environment variables have been modified.
      To see the exact flags applied, build with the --verbose option.

• Windows:

Cross compiling ....................... FALSE
Valgrind .............................. OFF
Preprocessor defined macros ........... ENABLE_MODULE_ELLSWIFT=1 ENABLE_MODULE_SCHNORRSIG=1 ENABLE_MODULE_EXTRAKEYS=1 ENABLE_MODULE_ECDH=1 ECMULT_WINDOW_SIZE=15 COMB_BLOCKS=11 COMB_TEETH=6 _CRT_SECURE_NO_WARNINGS
C compiler ............................ MSVC 19.40.33811.0, C:/Program Files/Microsoft Visual Studio/2022/Community/VC/Tools/MSVC/14.40.33807/bin/Hostx64/x64/cl.exe
Available build configurations ........ RelWithDebInfo, Release, Debug, MinSizeRel, Coverage
Default build configuration ........... Debug

'RelWithDebInfo' build configuration:
  C compiler flags .................... /DWIN32 /D_WINDOWS /Zi /O2 /Ob1 /W3 /wd4146 /wd4244 /wd4267
  Linker flags ........................ /machine:x64 /debug /INCREMENTAL

'Release' build configuration:
  C compiler flags .................... /DWIN32 /D_WINDOWS /O2 /Ob2 /W3 /wd4146 /wd4244 /wd4267
  Linker flags ........................ /machine:x64 /INCREMENTAL:NO

'Debug' build configuration:
  C compiler flags .................... /DWIN32 /D_WINDOWS /Zi /Ob0 /Od /RTC1 /W3 /wd4146 /wd4244 /wd4267
  Linker flags ........................ /machine:x64 /debug /INCREMENTAL

'MinSizeRel' build configuration:
  C compiler flags .................... /DWIN32 /D_WINDOWS /O1 /Ob1 /W3 /wd4146 /wd4244 /wd4267
  Linker flags ........................ /machine:x64 /INCREMENTAL:NO

'Coverage' build configuration:
  C compiler flags .................... /DWIN32 /D_WINDOWS /Zi /O2 /Ob1  -O0 -DCOVERAGE=1 --coverage /W3 /wd4146 /wd4244 /wd4267
  Linker flags ........................ /machine:x64 /debug /INCREMENTAL --coverage

NOTE: The summary above may not exactly match the final applied build flags
      if any additional CMAKE_* or environment variables have been modified.
      To see the exact flags applied, build with the --verbose option.

[real-or-random]

Concept ACK

The note is a bit verbose, but I don't have a convincing suggestion to shorten it.

[real-or-random]

Sorry, when I wrote the previous comment, I assumed this PR is in the hebasto/bitcoin repo for cmake staging... 🤦‍♂️ :

utACK aa4c5f3 this matches the implementation in hebasto/bitcoin#93 and has been revieed there

[fanquake]

Looks like this is at least missing link options like -compatibility_version 5.0.0 -current_version 5.1.0.

[fanquake]

Also flags like -fPIC are shown in the C compiler flags, but not shown in the linker flags?

[real-or-random]

Good observations. These should be fixed if the rule is as in this comment:

# Print tools' flags on best-effort. Include the abstracted
# CMake flags that we touch ourselves.

[hebasto]

Both @fanquake's comments have been addressed.

[fanquake]

Looks like this is at least missing link options like -compatibility_version 5.0.0 -current_version 5.1.0.

The same is still missing on Linux?

[hebasto]

All recent @fanquake's comments have been addressed.

[hebasto]

Fixed quoting of (potentially empty) string arguments.