Accept also macOS SDK 10.15

Change-Id: I2369db6b76af67d71146903c081ce6427d45c211

configure.ac

@@ -2735,7 +2735,7 @@ if test $_os = Darwin -o $_os = iOS; then
     # higher than or equal to the minimum required should be found.
 
     AC_MSG_CHECKING([what macOS SDK to use])
-    for _macosx_sdk in ${with_macosx_sdk-10.14 10.13 10.12}; do
+    for _macosx_sdk in ${with_macosx_sdk-10.15 10.14 10.13 10.12}; do
         MACOSX_SDK_PATH=`xcrun --sdk macosx${_macosx_sdk} --show-sdk-path 2> /dev/null`
         if test -d "$MACOSX_SDK_PATH"; then
             with_macosx_sdk="${_macosx_sdk}"
@@ -2773,8 +2773,11 @@ if test $_os = Darwin -o $_os = iOS; then
     10.14)
         MACOSX_SDK_VERSION=101400
         ;;
+    10.15)
+        MACOSX_SDK_VERSION=101500
+        ;;
     *)
-        AC_MSG_ERROR([with-macosx-sdk $with_macosx_sdk is not a supported value, supported values are 10.12--14])
+        AC_MSG_ERROR([with-macosx-sdk $with_macosx_sdk is not a supported value, supported values are 10.12--15])
         ;;
     esac
 
@@ -2819,8 +2822,11 @@ if test $_os = Darwin -o $_os = iOS; then
     10.14)
         MAC_OS_X_VERSION_MIN_REQUIRED="101400"
         ;;
+    10.15)
+        MAC_OS_X_VERSION_MIN_REQUIRED="101500"
+        ;;
     *)
-        AC_MSG_ERROR([with-macosx-version-min-required $with_macosx_version_min_required is not a supported value, supported values are 10.10--14])
+        AC_MSG_ERROR([with-macosx-version-min-required $with_macosx_version_min_required is not a supported value, supported values are 10.10--15])
         ;;
     esac
     MAC_OS_X_VERSION_MIN_REQUIRED_DOTS=$with_macosx_version_min_required
@@ -2860,8 +2866,11 @@ if test $_os = Darwin -o $_os = iOS; then
     10.14)
         MAC_OS_X_VERSION_MAX_ALLOWED="101400"
         ;;
+    10.15)
+        MAC_OS_X_VERSION_MAX_ALLOWED="101500"
+        ;;
     *)
-        AC_MSG_ERROR([with-macosx-version-max-allowed $with_macosx_version_max_allowed is not a supported value, supported values are 10.10--14])
+        AC_MSG_ERROR([with-macosx-version-max-allowed $with_macosx_version_max_allowed is not a supported value, supported values are 10.10--15])
         ;;
     esac