RED-560: Add support for STANDALONE to OPENAL.cmake

Use pkg_check_modules to find freealut (and openal) for STANDALONE.
Non-standalone is untouched by this version.

The changes relative to snowglobe (for the STANDALONE path) is
that I removed the 'include(FindOpenAL) (that comes with cmake)
which not only doesn't find libalut, but even sets the wrong
cmake variables (it sets OPENAL_LIBRARY, and our cmake scripts
*use* OPENAL_LIBRARIES). Moreover, under the assumption that
STANDALONE really is only for linux (and I think that is so),
every linux distribution DOES have freealut (and openal) installed
with a pkg-config anyway. I also removed pkg_check_modules(openal)
because it is redundant: freealut pulls that in already.

1 files changed, 12 insertions, 2 deletions

diff --git a/linden/indra/cmake/OPENAL.cmake b/linden/indra/cmake/OPENAL.cmake
index 4f0e0cc..b9efd57 100644
--- a/linden/indra/cmake/OPENAL.cmake
+++ b/linden/indra/cmake/OPENAL.cmake
@@ -2,11 +2,21 @@
 
 include(Variables)
 include(Linking)
+include(FindPkgConfig)
 
 set(OPENAL ON CACHE BOOL "Enable OpenAL")
 
+# If STANDALONE but NOT PKG_CONFIG_FOUND we should fail,
+# but why try to find it as prebuilt?
+if (OPENAL AND STANDALONE AND PKG_CONFIG_FOUND)
 
-if (OPENAL)
+  # This module defines
+  # OPENAL_INCLUDE_DIRS
+  # OPENAL_LIBRARIES
+  # OPENAL_FOUND
+  pkg_check_modules(OPENAL REQUIRED freealut)   # freealut links with openal.
+
+elseif (OPENAL)
 
   # message(STATUS "Building with OpenAL audio support")
 
@@ -110,4 +120,4 @@ if (OPENAL)
     "Found OpenAL and ALUT libraries successfully"
     )
 
-endif (OPENAL)
+endif (OPENAL AND STANDALONE AND PKG_CONFIG_FOUND)