CubicSDR: allow building back to OSX 10.7

Also make current builds cleaner via removing conflicting settings between MacPorts and the CMake script settings. Rev-bump just in case.

science/CubicSDR/Portfile

@@ -23,7 +23,7 @@ version             20190417-[string range ${github.version} 0 7]
 checksums           rmd160 9e54b818c5777fefce428995e99f8ee60a7249f7 \
                     sha256 a13e9a5b0b0f09dfa26395a5f4d63662999bdfea85e99f638cce05c7aada1a52 \
                     size   36027266
-revision            1
+revision            2
 
 wxWidgets.use       wxWidgets-3.2
 
@@ -59,10 +59,17 @@ variant bundle description {Enable the optional macOS bundle of CubicSDR} {
 
 default_variants-append +bundle
 
-# from documentation
-if {${os.platform} eq "darwin" && ${os.major} < 13} {
+# the readme -recommends- OSX 10.9 or later, but this is not really
+# required. Tweaking the top-level CMakeLists.txt to remove
+# constraints allows building at least back to OSX 10.7. Removing
+# these is also good practice since there are conflicts between what
+# macPorts provides (e.g., in CXXFLAGS) and what CubicSDR is trying to
+# set internal to the build.
+patchfiles-append patch-fix-build-older-osx.diff
+
+if {${os.platform} eq "darwin" && ${os.major} < 11} {
     pre-fetch {
-        ui_error "${subport} @${version} requires OS X 10.9 or newer"
+        ui_error "${subport} @${version} requires OS X 10.7 or newer"
         return -code error "unsupported Mac OS X version"
     }
 }

science/CubicSDR/files/patch-fix-build-older-osx.diff

@@ -0,0 +1,33 @@
+--- CMakeLists.txt.orig
++++ CMakeLists.txt
+@@ -299,10 +299,10 @@
+ ENDIF(UNIX AND NOT APPLE)
+
+ IF (APPLE)
+-    SET(CMAKE_OSX_DEPLOYMENT_TARGET, "10.9")
++#    SET(CMAKE_OSX_DEPLOYMENT_TARGET, "10.9")
+
+     SET(LIQUID_LIB liquid)
+-    link_directories(/usr/local/lib)
++#    link_directories(/usr/local/lib)
+     link_directories(/opt/local/lib)
+
+     ADD_DEFINITIONS(
+@@ -706,7 +706,7 @@
+ IF (APPLE)
+     ADD_DEFINITIONS(
+         -DHAVE_TYPE_TRAITS=1
+-        -mmacosx-version-min=10.9
++#        -mmacosx-version-min=10.9
+     )
+ ENDIF(APPLE)
+
+@@ -734,7 +734,7 @@
+     ENDIF()
+
+     ADD_DEFINITIONS(
+-        -std=c++0x 
++#        -std=c++0x 
+         -pthread
+         -D_OSX_APP_
+     )