[MacPorts] #62426: libc++: using a newer libc++ to build software on older macos systems

[MacPorts]

#62426: libc++: using a newer libc++ to build software on older macos systems
-------------------------------------+--------------------
  Reporter:  kencu                   |      Owner:  kencu
      Type:  enhancement             |     Status:  closed
  Priority:  Normal                  |  Milestone:
 Component:  ports                   |    Version:
Resolution:  fixed                   |   Keywords:
      Port:  libcxx macports-libcxx  |
-------------------------------------+--------------------

Comment (by RJVB):

 Checking an older Qt5 application:

 {{{
 > otool -L
 /Applications/MacPorts/Qt5/QtAssistant.app/Contents/MacOS/QtAssistant  |
 fgrep libc++
         /usr/lib/libc++.1.dylib (compatibility version 1.0.0, current
 version 120.0.0)

 > env DYLD_PRINT_LIBRARIES=1
 /Applications/MacPorts/Qt5/QtAssistant.app/Contents/MacOS/QtAssistant |&
 fgrep libc++
 dyld: loaded: /usr/lib/libc++.1.dylib
 dyld: loaded: /usr/lib/libc++abi.dylib

 > lsof +c 0 | fgrep -i QtAssistant | fgrep libc++
 Exit 1
 }}}

 I see this same result with another "pure Qt" application?! But:

 {{{
 > env DYLD_PRINT_LIBRARIES=1
 DYLD_INSERT_LIBRARIES=/opt/local/lib/libc++.dylib
 /Applications/MacPorts/Qt5/QtAssistant.app/Contents/MacOS/QtAssistant | &
 fgrep libc++
 dyld: loaded: /opt/local/lib/libc++.dylib
 dyld: loaded: /usr/lib/libc++.1.dylib
 dyld: loaded: /usr/lib/libc++abi.dylib
 dyld: loaded: /opt/local/lib/libc++abi.1.dylib

 > lsof +c 0 | fgrep -i QtAssistant | fgrep libc++
 QtAssistant           77231 bertin  txt      REG                1,1
 2223932  9538392 /opt/local/lib/libc++.1.dylib
 QtAssistant           77231 bertin  txt      REG                1,1
 617328  9538394 /opt/local/lib/libc++abi.1.dylib
 }}}

 A bit of hackery to see if I can make something go wrong:

 {{{
 > lsof +c 0 | fgrep kdevelop | fgrep libc++
 kdevelop.bin          69337 bertin  txt      REG                1,1
 2223932  9538392 /opt/local/lib/libc++.1.dylib
 kdevelop.bin          69337 bertin  txt      REG                1,1
 617328  9538394 /opt/local/lib/libc++abi.1.dylib
 kdevelop.bin          77002 bertin  txt      REG                1,1
 2223932  9538392 /opt/local/lib/libc++.1.dylib
 kdevelop.bin          77002 bertin  txt      REG                1,1
 617328  9538394 /opt/local/lib/libc++abi.1.dylib
 }}}

 > env DYLD_PRINT_LIBRARIES=1 DYLD_INSERT_LIBRARIES=/usr/lib/libc++.1.dylib
 /Applications/MacPorts/KF5/kdevelop.app/Contents/MacOS/kdevelop.bin --ps |
 & fgrep libc++
 dyld: loaded: /usr/lib/libc++.1.dylib
 dyld: loaded: /opt/local/lib/libc++.1.dylib
 dyld: loaded: /usr/lib/libc++abi.dylib
 dyld: loaded: /opt/local/lib/libc++abi.1.dylib

 >
 }}}

 {{{
 > sudo /opt/local/bin/install_name_tool -change
 /opt/local/lib/libc++.1.dylib /usr/lib/libc++.1.dylib
 /Applications/MacPorts/KF5/kdevelop.app/Contents/MacOS/kdevelop.bin

 > otool -L
 /Applications/MacPorts/KF5/kdevelop.app/Contents/MacOS/kdevelop.bin |
 fgrep libc++
         /usr/lib/libc++.1.dylib (compatibility version 1.0.0, current
 version 9.0.1)

 > lsof +c 0 | fgrep kdevelop | fgrep libc++
 kdevelop.bin          69337 bertin  txt      REG                1,1
 2223932  9538392 /opt/local/lib/libc++.1.dylib
 kdevelop.bin          69337 bertin  txt      REG                1,1
 617328  9538394 /opt/local/lib/libc++abi.1.dylib
 kdevelop.bin          76908 bertin  txt      REG                1,1
 2223932  9538392 /opt/local/lib/libc++.1.dylib
 kdevelop.bin          76908 bertin  txt      REG                1,1
 617328  9538394 /opt/local/lib/libc++abi.1.dylib
 }}}

 Note how install_name_tool did NOT change the `current_version` info
 stored in KDevelop!!

-- 
Ticket URL: <https://trac.macports.org/ticket/62426#comment:54>
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