Introduce first class support for Android (#5772)

lib/pure/nativesockets.nim

@@ -233,7 +233,7 @@ proc getAddrInfo*(address: string, port: Port, domain: Domain = AF_INET,
   # OpenBSD doesn't support AI_V4MAPPED and doesn't define the macro AI_V4MAPPED.
   # FreeBSD doesn't support AI_V4MAPPED but defines the macro.
   # https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=198092
-  when not defined(freebsd) and not defined(openbsd) and not defined(netbsd):
+  when not defined(freebsd) and not defined(openbsd) and not defined(netbsd) and not defined(android):
     if domain == AF_INET6:
       hints.ai_flags = AI_V4MAPPED
   var gaiResult = getaddrinfo(address, $port, addr(hints), result)

lib/pure/ospaths.nim

@@ -528,11 +528,26 @@ when declared(getEnv) or defined(nimscript):
     elif getEnv("XDG_CONFIG_DIR"): return string(getEnv("XDG_CONFIG_DIR")) & "/"
     else: return string(getEnv("HOME")) & "/.config/"
 
+  when defined(android):
+    {.pragma: getTempDirEffects, tags: [ReadEnvEffect, ReadIOEffect, WriteDirEffect].}
+  elif defined(windows):
+    {.pragma: getTempDirEffects, tags: [ReadEnvEffect, ReadIOEffect].}
+  else:
+    {.pragma: getTempDirEffects, tags: [ReadIOEffect].}
+
   proc getTempDir*(): string {.rtl, extern: "nos$1",
-    tags: [ReadEnvEffect, ReadIOEffect].} =
+    getTempDirEffects.} =
     ## Returns the temporary directory of the current user for applications to
     ## save temporary files in.
-    when defined(windows): return string(getEnv("TEMP")) & "\\"
+    when defined(tempDir):
+      const tempDir {.strdefine.}: string = nil
+      return tempDir
+    elif defined(windows): return string(getEnv("TEMP")) & "\\"
+    elif defined(android):
+      let tempDir = getHomeDir() / "nimtempfs"
+      try: createDir(tempDir)
+      except OSError: discard
+      return tempDir
     else: return "/tmp/"
 
   proc expandTilde*(path: string): string {.

lib/pure/osproc.nim

@@ -762,7 +762,8 @@ elif not defined(useNimRtl):
     var sysCommand: string
     var sysArgsRaw: seq[string]
     if poEvalCommand in options:
-      sysCommand = "/bin/sh"
+      const useShPath {.strdefine.} = "/bin/sh"
+      sysCommand = useShPath
       sysArgsRaw = @[sysCommand, "-c", command]
       assert args.len == 0, "`args` has to be empty when using poEvalCommand."
     else: