exchange the definitions of SEQUOIA_LDFLAGS and SEQUOIA_LIB , which were used incorrectly

See the Autoconf manual, §{Preset Output Variables} about the variables LDFLAGS
and LIBS.

Makefile.conf

@@ -342,10 +342,10 @@ ifeq ($(SEQUOIA_CFLAGS),)
     SEQUOIA_CFLAGS+=$(shell pkg-config --cflags-only-other pep_engine_sequoia_backend) -O2
 endif
 ifeq ($(SEQUOIA_LDFLAGS),)
-    SEQUOIA_LDFLAGS+=$(shell pkg-config --libs-only-l pep_engine_sequoia_backend)
+    SEQUOIA_LDFLAGS+=$(shell pkg-config --libs-only-L pep_engine_sequoia_backend)
 endif
 ifeq ($(SEQUOIA_LIB),)
-    SEQUOIA_LIB=$(shell pkg-config --libs-only-L --libs-only-other pep_engine_sequoia_backend)
+    SEQUOIA_LIB=$(shell pkg-config --libs-only-l --libs-only-other pep_engine_sequoia_backend)
 endif
 ifeq ($(SEQUOIA_INC),)
     SEQUOIA_INC=$(shell pkg-config --cflags-only-I pep_engine_sequoia_backend)