Fix included linker scripts with no newline at EOF (#2011)

test/link/linkerscript-no-newline-eof.asm

@@ -0,0 +1,2 @@
+section "test", rom0[1337]
+label:: dw label

test/link/linkerscript-no-newline-eof.inc

@@ -0,0 +1 @@
+rom0 ; no newline after this

test/link/linkerscript-no-newline-eof.link

@@ -0,0 +1,2 @@
+include "linkerscript-no-newline-eof.inc"
+	"test" ; no newline after this

test/link/linkerscript-no-newline-eof.out

@@ -0,0 +1,3 @@
+error: The linker script assigns section "test" to address $0000, but it was already at $0539
+    at linkerscript-no-newline-eof.link(2)
+Linking failed with 1 error