[ Makefile ] Removed RELEASE variable.

The variable was added in
ae56973
because in the release candidate Makefile, the $VERSION variable was
empty. However, the release candidates shouldn't include the Makefile
(see #1482 (comment)).

Makefile

@@ -19,19 +19,11 @@ CABAL_CMD=cabal
 
 override CABAL_OPTS+=--builddir=$(BUILD_DIR)
 
-ifndef RELEASE
+# --program-suffix is not for the executable name in
+# $(BUILD_DIR)/build/, only for installing it into .cabal/bin
+override CABAL_OPTS+=--program-suffix=-$(VERSION)
 
-  # --program-suffix is not for the executable name in
-  # $(BUILD_DIR)/build/, only for installing it into .cabal/bin
-  override CABAL_OPTS+=--program-suffix=-$(VERSION)
-
-  AGDA_MODE=agda-mode-$(VERSION)
-
-else
-
-  AGDA_MODE=agda-mode
-
-endif
+AGDA_MODE=agda-mode-$(VERSION)
 
 # Run in interactive and parallel mode by default
 AGDA_TESTS_OPTIONS ?=-i -j $(shell getconf _NPROCESSORS_ONLN)

notes/agda-maintenance-releases

@@ -31,12 +31,6 @@ followed:
 
 * Update the LICENSE file, if necessary.
 
-* Add the line
-
-    RELEASE=true
-
-  at the top of the Makefile.
-
 * Add a second source-repository section to Agda.cabal:
 
     source-repository this
@@ -117,12 +111,6 @@ followed:
   file. (This would be unnecessary if we had two repositories, one
   stable and one for development.)
 
-* Remove the line
-
-    RELEASE=true
-
-  from the top of the Makefile.
-
 * Add a new header to CHANGELOG.
 
 * Update the version numbers in