[MacPorts] #64590: libgcrypt: Configuration logfiles contain indications of -Wimplicit-function-declaration in "fn"

[MacPorts]

#64590: libgcrypt: Configuration logfiles contain indications of -Wimplicit-
function-declaration in "fn"
------------------------+--------------------------------------------
  Reporter:  judaew     |      Owner:  Schamschula
      Type:  defect     |     Status:  assigned
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:  2.7.1
Resolution:             |   Keywords:  wimplicit-function-declaration
      Port:  libgcrypt  |
------------------------+--------------------------------------------

Comment (by ryandesign):

 This check for `fn` occurs during "checking whether GCC assembler handles
 division correctly". The premise of the configure check seems faulty to
 me, since we are not using the GCC inline assembler. Perhaps the configure
 script should first ascertain whether the GCC inline assembler is being
 used, and only then perform more specific tests on it.

 There are three ways of hiding these messages.

 1. If the function being checked exists on macOS (or in an external
 library the project is trying to use), fix the code to include the header
 where that function is defined.
 2. If the function being checked does not exist on macOS, add it to the
 [browser:macports-
 ports/_resources/port1.0/checks/implicit_function_declaration global
 ignore files].
 3. If the function being checked does exist on macOS but this portfile's
 build system is intentionally doing something weird and checking for its
 existence without including the right header (for example recent
 autoconf's check for `strchr` without including the right header in order
 to see how the compiler reacts to that), add the exclusion to the portfile
 itself by appending the function's name to
 `configure.checks.implicit_function_declaration.whitelist`.

-- 
Ticket URL: <https://trac.macports.org/ticket/64590#comment:2>
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