Recognise uclinux as a linux

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

diff -durN sg3_utils-1.42.orig/configure.ac sg3_utils-1.42/configure.ac
--- sg3_utils-1.42.orig/configure.ac	2015-10-21 01:10:59.000000000 +0200
+++ sg3_utils-1.42/configure.ac	2016-08-14 19:30:37.841766149 +0200
@@ -71,7 +71,7 @@
 
 # Define platform-specific symbol.
 AM_CONDITIONAL(OS_FREEBSD, [echo $host_os | grep 'freebsd' > /dev/null])
-AM_CONDITIONAL(OS_LINUX, [echo $host_os | grep '^linux' > /dev/null])
+AM_CONDITIONAL(OS_LINUX, [echo $host_os | grep -E '^(uc)?linux' > /dev/null])
 AM_CONDITIONAL(OS_OSF, [echo $host_os | grep '^osf' > /dev/null])
 AM_CONDITIONAL(OS_SOLARIS, [echo $host_os | grep '^solaris' > /dev/null])
 AM_CONDITIONAL(OS_WIN32_MINGW, [echo $host_os | grep '^mingw' > /dev/null])