Update to main-snapshot-2026-05-18 (#200)

Updates the `.swift-version` file to Swift `main-snapshot-2026-05-18`.

> This PR was automatically generated.

Co-authored-by: github-actions <github-actions@users.noreply.github.com>
Co-authored-by: Rauhul Varma <rauhul@apple.com>

Author: 3 people

.swift-version

@@ -1 +1 @@
-main-snapshot-2026-03-16
+main-snapshot-2026-05-18

stm32-blink/Makefile

@@ -15,11 +15,13 @@ TOOLSROOT        := $(REPOROOT)/Tools
 TOOLSET          := $(TOOLSROOT)/Toolsets/stm32f74x.json
 MACHO2BIN        := $(TOOLSROOT)/macho2bin.py
 SWIFT_BUILD      := swift build
+BUILD_SYSTEM     := native
 
 # Flags
 ARCH             := armv7em
 TARGET           := $(ARCH)-apple-none-macho
 SWIFT_BUILD_ARGS := \
+	--build-system $(BUILD_SYSTEM) \
 	--configuration release \
 	--triple $(TARGET) \
 	--toolset $(TOOLSET)

stm32-lcd-logo/Makefile

@@ -15,11 +15,13 @@ TOOLSROOT        := $(REPOROOT)/Tools
 TOOLSET          := $(TOOLSROOT)/Toolsets/stm32f74x-lcd.json
 MACHO2BIN        := $(TOOLSROOT)/macho2bin.py
 SWIFT_BUILD      := swift build
+BUILD_SYSTEM     := native
 
 # Flags
 ARCH             := armv7em
 TARGET           := $(ARCH)-apple-none-macho
 SWIFT_BUILD_ARGS := \
+	--build-system $(BUILD_SYSTEM) \
 	--configuration release \
 	--triple $(TARGET) \
 	--toolset $(TOOLSET)

stm32-lvgl/Makefile

@@ -15,6 +15,7 @@ TOOLSROOT        := $(REPOROOT)/Tools
 TOOLSET          := $(PWD)/toolset.json
 ELF2HEX          := $(TOOLSROOT)/elf2hex.py
 SWIFT_BUILD      := swift build
+BUILD_SYSTEM     := native
 NM               := nm
 LLVM_TOOLCHAIN   := $(PWD)/llvm-toolchain
 BUILD_SYSTEM     := native
@@ -82,6 +83,7 @@ simulator:
 
 	@echo "building..."
 	$(SWIFT_BUILD) \
+	    --build-system $(BUILD_SYSTEM) \
 	    --configuration release \
 		--product HostSDLApp \
 		--verbose