Enable adding JSON1 by appending the json1.c source file to the amalgamation

and compiling with -DSQLITE_ENABLE_JSON1

FossilOrigin-Name: 33404b2029120d4aabe1e25d484871810777e934

main.mk

@@ -454,7 +454,7 @@ FUZZDATA = \
 # Extra arguments for including json1 in the build of tools
 #
 JSON1_DEP = $(TOP)/ext/misc/json1.c sqlite3ext.h
-JSON1_OPT = -DSQLITE_ENABLE_JSON1 -DSQLITE_CORE
+JSON1_OPT = -DSQLITE_SHELL_JSON1 -DSQLITE_CORE
 JSON1_SRC = $(TOP)/ext/misc/json1.c
 
 # Standard options to testfixture
@@ -532,6 +532,9 @@ sqlite3.c:	target_source $(TOP)/tool/mksqlite3c.tcl
 	echo '#endif /* USE_SYSTEM_SQLITE */' >>tclsqlite3.c
 	cat $(TOP)/src/tclsqlite.c >>tclsqlite3.c
 
+sqlite3ext.h:	target_source
+	cp tsrc/sqlite3ext.h .
+
 sqlite3.c-debug:	target_source $(TOP)/tool/mksqlite3c.tcl
 	tclsh $(TOP)/tool/mksqlite3c.tcl --linemacros
 	echo '#ifndef USE_SYSTEM_SQLITE' >tclsqlite3.c