make: revert/correct fix for plain undef symbol.

The return value from _error was causing some breakage in other error
handling. Instead, return a value from the spot where the undefined
symbol error is set. This achieves the desired fix without breaking
other unclosed sequence errors.

Author: kanaka

make/env.mk

@@ -43,7 +43,7 @@ ENV_FIND = $(strip \
                  ,\
                  $(call ENV_FIND,$(call _get,$(1),__outer__),$(2)))))
 
-ENV_GET = $(foreach env,|$(call ENV_FIND,$(1),$(2))|,$(if $(call _EQ,||,$(env)),$(call _error,'$(2)' not found),$(call _get,$(strip $(subst |,,$(env))),$(subst =,$(__equal),$(2)))))
+ENV_GET = $(foreach env,|$(call ENV_FIND,$(1),$(2))|,$(if $(call _EQ,||,$(env)),$(call _error,'$(2)' not found)$(__nil),$(call _get,$(strip $(subst |,,$(env))),$(subst =,$(__equal),$(2)))))
 
 ENV_SET = $(if $(call _assoc!,$(1),$(subst =,$(__equal),$(2)),$(3)),$(1),)
 

make/types.mk

@@ -68,18 +68,18 @@ __var_print = $(foreach v,$(1),\
 _visualize_memory = $(foreach var,$(sort $(foreach vv,$(filter $(__obj_magic)_%,$(.VARIABLES)),$(call __var_name,$(vv)))),$(call __var_print,$(__obj_magic)_$(var)))
 
 
+# Errors/Exceptions
+__ERROR :=
+_error = $(strip $(eval __ERROR := $(call _string,$(1))))
+
+
 # Constant atomic values
 __undefined = $(__obj_magic)_undf_0
 __nil = $(__obj_magic)__nil_0
 __true = $(__obj_magic)_true_0
 __false = $(__obj_magic)_fals_0
 
 
-# Errors/Exceptions
-__ERROR :=
-_error = $(eval __ERROR := $(call _string,$(1)))$(__nil)
-
-
 # General functions
 
 # Return the type of the object (or "make" if it's not a object