Unknown name error, implicit function declarations building on Windows 10

[jamiltron]

With the latest msi-installed meson/ninja, I get several compiler errors when running ninja, most seem to be unknown types or implicit function declarations. Here's the first:

[7/25] Compiling C object src/libepoxy-0.dll.p/dispatch_wgl.c.obj
FAILED: src/libepoxy-0.dll.p/dispatch_wgl.c.obj
"cc" "-Isrc\libepoxy-0.dll.p" "-Isrc" "-I..\src" "-Iinclude" "-I..\include" "-Iinclude\epoxy" "-fdiagnostics-color=always" "-pipe" "-D_FILE_OFFSET_BITS=64" "-Wall" "-Winvalid-pch" "-std=gnu99" "-O2" "-g" "-Wpointer-arith" "-Wmissing-declarations" "-Wformat=2" "-Wstrict-prototypes" "-Wmissing-prototypes" "-Wnested-externs" "-Wbad-function-cast" "-Wold-style-definition" "-Wdeclaration-after-statement" "-Wunused" "-Wuninitialized" "-Wshadow" "-Wmissing-noreturn" "-Wmissing-format-attribute" "-Wredundant-decls" "-Wlogical-op" "-Werror=implicit" "-Werror=nonnull" "-Werror=init-self" "-Werror=main" "-Werror=missing-braces" "-Werror=sequence-point" "-Werror=return-type" "-Werror=trigraphs" "-Werror=array-bounds" "-Werror=write-strings" "-Werror=address" "-Werror=int-to-pointer-cast" "-Werror=pointer-to-int-cast" "-fno-strict-aliasing" "-Wno-int-conversion" "-fvisibility=hidden" -MD -MQ src/libepoxy-0.dll.p/dispatch_wgl.c.obj -MF "src\libepoxy-0.dll.p\dispatch_wgl.c.obj.d" -o src/libepoxy-0.dll.p/dispatch_wgl.c.obj "-c" ../src/dispatch_wgl.c
../src/dispatch_wgl.c: In function 'epoxy_conservative_has_wgl_extension':
../src/dispatch_wgl.c:41:5: error: unknown type name 'HDC'
   41 |     HDC hdc = wglGetCurrentDC();
      |     ^~~

It looks like ninja is using my msys gcc, but I have also tried running this through the visual studio developer console with similar issues.