OS X shell is incompatible with echo -n

Built in echo in 'sh' on OS X does not support -n (exclude trailing
newline). It's not necessary so just leave it off. Fixes issue 390.

Build include guard using 'symbol' so that it is more likely to be
unique.

Change-Id: I4bc6aa1fc5e02228f71c200214b5ee4a16d56b83

build/make/rtcd.sh

diff --git a/build/make/rtcd.sh b/build/make/rtcd.sh
index a5f1e6d..1dffde5 100755
--- a/build/make/rtcd.sh
+++ b/build/make/rtcd.sh
@@ -196,8 +196,8 @@
 # Helper functions for generating the arch specific RTCD files
 #
 common_top() {
-  local outfile_basename=$(basename ${outfile:-rtcd.h})
-  local include_guard=$(echo -n $outfile_basename | tr '[a-z]' '[A-Z]' | tr -c '[A-Z]' _)
+  local outfile_basename=$(basename ${symbol:-rtcd.h})
+  local include_guard=$(echo $outfile_basename | tr '[a-z]' '[A-Z]' | tr -c '[A-Z]' _)
   cat <<EOF
 #ifndef ${include_guard}
 #define ${include_guard}
@@ -225,7 +225,7 @@
 
   # Assign the helper variable for each enabled extension
   for opt in $ALL_ARCHS; do
-    local uc=$(echo -n $opt | tr '[a-z]' '[A-Z]')
+    local uc=$(echo $opt | tr '[a-z]' '[A-Z]')
     eval "have_${opt}=\"flags & HAS_${uc}\""
   done
 
@@ -253,7 +253,7 @@
 
   # Assign the helper variable for each enabled extension
   for opt in $ALL_ARCHS; do
-    local uc=$(echo -n $opt | tr '[a-z]' '[A-Z]')
+    local uc=$(echo $opt | tr '[a-z]' '[A-Z]')
     eval "have_${opt}=\"flags & HAS_${uc}\""
   done