diff --git a/.travis.yml b/.travis.yml
index 31a5169..406918a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,7 +2,6 @@ language: cpp
 
 os:
     - linux
-    - osx
 
 compiler:
     - gcc
@@ -15,6 +14,9 @@ addons:
     packages:
       - cmake
 
+before_install:
+  - export LD_LIBRARY_PATH=$(if [[ $C == "clang" ]]; then echo -n '/usr/local/clang/lib'; fi)
+
 before_script:
   - mkdir build
   - cd build
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 27c0aee..46e1822 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -60,6 +60,9 @@ else()
 	set(VERSION_GIT_FULL "${VERSION_GIT}-${VERSION_GIT_IS_DIRTY}")
 endif()
 
+include(CheckSymbolExists)
+check_symbol_exists(posix_fadvise fcntl.h HAVE_POSIX_FADVISE)
+
 add_subdirectory(src)
 
 # tests
diff --git a/README.md b/README.md
index 21f89a2..6d7eab2 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ Precise map-matching for public transit schedules (GTFS data).
 ## Requirements
 
  * `cmake`
- * `gcc >= 4.8`
+ * `gcc >= 4.8` (or `clang >= 5.0`)
 
 ## Building and Installation