build: Android support.

* Makefile (conftest.android): New helper target for testing
for Android toolchain, via presence of __ANDROID__
preprocessor symbol, similarly to how we detect Darwin.

* configure: New test for Android.  This is mutually exclusive
agains Darwin. On Android, we add some necessary feature
selection macros to the compiler command line.

2 files changed, 22 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index dd7a2a11..6749a145 100644
--- a/Makefile
+++ b/Makefile
@@ -566,6 +566,12 @@ conftest.darwin:
 	  echo yes ; \
 	fi
 
+.PHONY: conftest.android
+conftest.android:
+	$(V)if echo | $(CC) -dM -E - | grep -s __ANDROID__ >  /dev/null 2>&1 ; then \
+	  echo yes ; \
+	fi
+
 .PHONY: conftest.clean
 conftest.clean:
 	$(V)rm -f conftest$(EXE) conftest.[co] \
diff --git a/configure b/configure
index ee52e460..5c3fd974 100755
--- a/configure
+++ b/configure
@@ -202,6 +202,7 @@ termios_define=
 have_pkgconfig=
 libffi_cflags=
 darwin_target=
+android_target=
 
 #
 # Parse configuration variables
@@ -1143,6 +1144,21 @@ else
   printf "no\n"
 fi
 
+if ! [ $darwin_target ] ; then
+  printf "Checking for Android environment ... "
+
+  if [ "$(make conftest.android)" = "yes" ] ; then
+    printf "yes\n"
+    android_target=y
+    lang_flags="$lang_flags -D__ANDROID_API__=65535 -D_BSD_SOURCE"
+    printf "Regenerating config.make ..."
+    gen_config_make
+    printf "done\n"
+  else
+    printf "no\n"
+  fi
+fi
+
 #
 # Detect stupid FreeBSD problem: no defined way to reveal
 # traditional BSD functions if Unix compliance is selected with