Revert "Fix Android cross-compile build: `cargo build --target armv7-linux-androideabi`"

This reverts commit ef250445c1.

lmdb-sys/build.rs

@@ -11,12 +11,7 @@ fn main() {
     lmdb.push("liblmdb");
 
     if !pkg_config::find_library("liblmdb").is_ok() {
-        let target = env::var("TARGET").expect("No TARGET found");
-        let mut build = cc::Build::new();
-        if target.contains("android") {
-            build.define("ANDROID", "1");
-        }
-        build
+        cc::Build::new()
                     .file(lmdb.join("mdb.c"))
                     .file(lmdb.join("midl.c"))
                     // https://github.com/LMDB/lmdb/blob/LMDB_0.9.21/libraries/liblmdb/Makefile#L25