[UnifiedPDF] CGPDFPageLayoutGetAreaOfInterestAtPoint should be declar…

…ed with C linkage

https://bugs.webkit.org/show_bug.cgi?id=266094
rdar://119394292

Reviewed by Wenson Hsieh.

Since CGPDFPageLayoutGetAreaOfInterestAtPoint is a C API, it must not go
through name mangling, so we specify C linkage for it.

This patch fixes the open source macOS build with unified PDF enabled.

* Source/WebCore/PAL/pal/spi/cg/CoreGraphicsSPI.h:

Canonical link: https://commits.webkit.org/271792@main

Source/WebCore/PAL/pal/spi/cg/CoreGraphicsSPI.h

@@ -247,8 +247,13 @@ typedef CF_OPTIONS(uint32_t, CGPDFAreaOfInterest) {
     kCGPDFAreaImage  = (1 << 1),
 };
 typedef struct CGPDFPageLayout *CGPDFPageLayoutRef;
+
+WTF_EXTERN_C_BEGIN
+
 CGPDFAreaOfInterest CGPDFPageLayoutGetAreaOfInterestAtPoint(CGPDFPageLayoutRef, CGPoint);
 
+WTF_EXTERN_C_END
+
 #endif // ENABLE(UNIFIED_PDF)
 
 #endif // USE(APPLE_INTERNAL_SDK)