Require C99

diff --git a/INSTALL b/INSTALL
index 0ff0d32..dd292c7 100644 (file)
--- a/INSTALL
+++ b/INSTALL
@@ -1,6 +1,23 @@
+============
+Installation
+============
+
 The most common installation procedure looks as follows.
 
 Unpack the tar archive and change into the unpacked directory.
 
   ./configure
   make check install
+
+
+=======================
+Intel compiler settings
+=======================
+
+The Intel compiler can improve performance by vectorizing certain
+parts of the code on x86 architectures.
+
+  ./configure CC=icc
+  make CFLAGS="-O3 -xCORE-AVX2"
+
+This assumes that you have a CPU which supports AVX2.

diff --git a/configure.ac b/configure.ac
index 35a6f0c..1d24da0 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -12,6 +12,7 @@ AM_INIT_AUTOMAKE
 
 # Checks for programs.
 AC_PROG_CC
+AC_PROG_CC_C99
 
 # Checks for libraries.
 AC_CHECK_LIB([aec], [aec_decode])