[MacPorts] #42594: llvm-3.3: ./configure: line 1990: -Os: command not found

[MacPorts]

#42594: llvm-3.3: ./configure: line 1990: -Os: command not found
------------------------------+------------------------
  Reporter:  Peter_Dyballa@…  |      Owner:  jeremyhu@…
      Type:  defect           |     Status:  new
  Priority:  Normal           |  Milestone:
 Component:  ports            |    Version:  2.2.1
Resolution:                   |   Keywords:
      Port:  llvm-3.3         |
------------------------------+------------------------

Comment (by larryv@…):

 Replying to [comment:1 ryandesign@…]:
 > Lines 1990-1991 of the configure script read:
 >
 > {{{
 > ${CFLAGS=}
 > ${CXXFLAGS=}
 > }}}
 >
 > I don't know what that's supposed to mean.

 These are special shell
 [http://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
 parameter expansions], intended to assign default values. Given an
 expansion `${FOO=bar}`:
 - If `FOO` has a value (including null), that value is substituted.
 - If `FOO` is unset, it is assigned the value `bar`, which is then
 substituted.

 So these lines are intended to set `CFLAGS` and `CXXFLAGS` to be null if
 they aren’t already set in the invoking environment. It’s a bit of an
 obtuse method of accomplishing this.

 > In llvm-3.2, which does not produce this message, these lines are
 > absent. In llvm-3.4 and llvm-3.5, which do not produce this message,
 > the lines instead read:
 >
 > {{{
 > : ${CFLAGS=}
 > : ${CXXFLAGS=}
 > }}}
 >
 > I still don't know what that's supposed to mean.

 The [http://pubs.opengroup.org/onlinepubs/009695399/utilities/colon.html
 colon] utility is a kind of weird no-op, except it still expands its
 arguments. So this accomplishes the same default-value behavior, except it
 avoids invoking a nonexistent command composed of compiler flags.

-- 
Ticket URL: <https://trac.macports.org/ticket/42594#comment:2>
MacPorts <http://www.macports.org/>
Ports system for OS X