*-wrapper; Switch from infixSalt to suffixSalt

I hate the thing too even though I made it, and rather just get rid of
it. But we can't do that yet. In the meantime, this brings us more
inline with autoconf and will make it slightly easier for me to write a
pkg-config wrapper, which we need.

pkgs/build-support/wrapper-common/utils.bash

@@ -1,29 +1,29 @@
-# Accumulate infixes for taking in the right input parameters with the `mangle*`
+# Accumulate suffixes for taking in the right input parameters with the `mangle*`
 # functions below. See setup-hook for details.
 accumulateRoles() {
-    declare -ga role_infixes=()
-    if [ "${NIX_@wrapperName@_@infixSalt@_TARGET_BUILD:-}" ]; then
-        role_infixes+=(_BUILD_)
+    declare -ga role_suffixes=()
+    if [ "${NIX_@wrapperName@_TARGET_BUILD_@suffixSalt@:-}" ]; then
+        role_suffixes+=('_FOR_BUILD')
     fi
-    if [ "${NIX_@wrapperName@_@infixSalt@_TARGET_HOST:-}" ]; then
-        role_infixes+=(_)
+    if [ "${NIX_@wrapperName@_TARGET_HOST_@suffixSalt@:-}" ]; then
+        role_suffixes+=('')
     fi
-    if [ "${NIX_@wrapperName@_@infixSalt@_TARGET_TARGET:-}" ]; then
-        role_infixes+=(_TARGET_)
+    if [ "${NIX_@wrapperName@_TARGET_TARGET_@suffixSalt@:-}" ]; then
+        role_suffixes+=('_FOR_TARGET')
     fi
 }
 
 mangleVarList() {
     local var="$1"
     shift
-    local -a role_infixes=("$@")
+    local -a role_suffixes=("$@")
 
-    local outputVar="${var/+/_@infixSalt@_}"
+    local outputVar="${var}_@suffixSalt@"
     declare -gx ${outputVar}+=''
     # For each role we serve, we accumulate the input parameters into our own
     # cc-wrapper-derivation-specific environment variables.
-    for infix in "${role_infixes[@]}"; do
-        local inputVar="${var/+/${infix}}"
+    for suffix in "${role_suffixes[@]}"; do
+        local inputVar="${var}${suffix}"
         if [ -v "$inputVar" ]; then
             export ${outputVar}+="${!outputVar:+ }${!inputVar}"
         fi
@@ -33,12 +33,12 @@ mangleVarList() {
 mangleVarBool() {
     local var="$1"
     shift
-    local -a role_infixes=("$@")
+    local -a role_suffixes=("$@")
 
-    local outputVar="${var/+/_@infixSalt@_}"
+    local outputVar="${var}_@suffixSalt@"
     declare -gxi ${outputVar}+=0
-    for infix in "${role_infixes[@]}"; do
-        local inputVar="${var/+/${infix}}"
+    for suffix in "${role_suffixes[@]}"; do
+        local inputVar="${var}${suffix}"
         if [ -v "$inputVar" ]; then
             # "1" in the end makes `let` return success error code when
             # expression itself evaluates to zero.