Fix FLOATING in linker scripts conflicting with section constraints (#2148)

test/link/floating-constraints.asm

@@ -0,0 +1,9 @@
+DEF address EQU $100
+
+SECTION "code", ROM0[address]
+
+Start::
+	jp Start
+
+assert STARTOF("code") == address
+assert Start == address

test/link/floating-constraints.link

@@ -0,0 +1,3 @@
+ROM0
+	FLOATING
+	"code"

test/link/linkerscript-floating-conflict.asm

@@ -0,0 +1,11 @@
+SECTION "fixed", ROM0[$1234]
+
+SECTION "aligned", ROMX, ALIGN[8, 42]
+
+SECTION "less aligned", ROMX, ALIGN[4, 1]
+
+SECTION "more aligned", ROMX, ALIGN[8, 1]
+
+SECTION "address compatible", ROMX[$4463]
+
+SECTION "align compatible", ROMX, ALIGN[8, 99]

test/link/linkerscript-floating-conflict.link

@@ -0,0 +1,21 @@
+ROM0
+	FLOATING
+	ALIGN 8, 42
+	"fixed"
+ROMX 1
+	FLOATING
+	ALIGN 8, 23
+	"aligned"
+ROMX 2
+	FLOATING
+	ALIGN 8, 2
+	"less aligned"
+ROMX 3
+	FLOATING
+	ALIGN 4, 2
+	"more aligned"
+ROMX 4
+	FLOATING
+	ALIGN 8, 99
+	"address compatible"
+	"align compatible"

test/link/linkerscript-floating-conflict.out

@@ -0,0 +1,9 @@
+error: The linker script aligns floating section "fixed" to ALIGN[8, 42], but it was already at address $1234 which has ALIGN[8, 52]
+    at linkerscript-floating-conflict.link(4)
+error: The linker script aligns floating section "aligned" to ALIGN[8, 23], but it already has requested ALIGN[8, 42]
+    at linkerscript-floating-conflict.link(8)
+error: The linker script aligns floating section "less aligned" to ALIGN[8, 2], but it already has requested ALIGN[4, 1]
+    at linkerscript-floating-conflict.link(12)
+error: The linker script aligns floating section "more aligned" to ALIGN[4, 2], but it already has requested ALIGN[8, 1]
+    at linkerscript-floating-conflict.link(16)
+Linking failed with 4 errors