diff --git a/configure.ac b/configure.ac
index 54f16a4fcb0ff8f566201d4c97c8f560d42aa071..e293a0135c6188a4613130c2854f606623bcf09e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -388,7 +388,7 @@ AS_IF([test "x$enable_video" != "xno"],
       [
         AC_DEFINE(RING_VIDEO, [], [Video support enabled])
         AM_CONDITIONAL(RING_VIDEO, true)
-        AS_IF([test "$SYS" = linux],[
+        AS_IF([test "$SYS" = linux && test -z "${HAVE_ANDROID_FALSE}"],[
             PKG_CHECK_MODULES(UDEV, libudev,, AC_MSG_ERROR([Missing libudev development files]))
         ],[
         ])
diff --git a/src/rational.h b/src/rational.h
index 681f8fc4f4704c41a688867c84a2ca4bc4ecdb6b..023221d66f238e1a9a8dca157349a0358cc83c49 100644
--- a/src/rational.h
+++ b/src/rational.h
@@ -31,7 +31,9 @@
 
 #pragma once
 
+#include <utility> // std::swap
 #include <cstdlib> // std::abs
+#include <iostream>
 
 namespace ring {
 
diff --git a/src/string_utils.h b/src/string_utils.h
index 6e09f64f844c09b01fdf8d8676378d0132b04d4b..b23470f4e0caed2869a912b9a5fbb2a204670ce5 100644
--- a/src/string_utils.h
+++ b/src/string_utils.h
@@ -59,7 +59,7 @@ bool_to_str(bool b) noexcept
 // We implement them by ourself as well as possible here.
 
 template <typename T>
-std::string
+inline std::string
 to_string(T &&value)
 {
     std::ostringstream os;
@@ -67,7 +67,7 @@ to_string(T &&value)
     return os.str();
 }
 
-int
+static inline int
 stoi(const std::string& str)
 {
     int v;